Bad website design: 12 costly mistakes we have seen (and how to fix them)

I have a confession. I do not like the word "website."

It is too vague, too broad, and it sets the wrong expectations from the very first conversation. Over the past 13 years at kwiboo, friends and clients have asked me the same question hundreds of times: "Can you build me a website?" Often followed by, "It is only a couple of pages. A home page, an about us, and a shop."

Only a couple of pages. With a shop.

Some have even had the cheek to say it as though it is a small favour. As if an e-commerce site is something you knock together over a weekend. In reality, an online shop means product management, payment processing, stock control, shipping logic, user accounts, security, and dozens of moving parts that all need to work together seamlessly. Calling it "a website" is like calling a Formula 1 car "a vehicle." Technically correct. Practically useless.

At kwiboo, most of what we build are bespoke SaaS platforms bespoke SaaS platforms delivered through a browser. Are they websites? Technically, yes. But they are a completely different animal to a five-page brochure site. The complexity, the architecture, the user experience considerations are on another level entirely.

Here is the thing, though. Whether you are running a simple portfolio site, an online shop, or a full-blown SaaS platform, the design mistakes that cost you customers are the same. Bad navigation is bad navigation. Slow loading is slow loading. Poor accessibility excludes people regardless of what you call the thing they are trying to use.

So for the purposes of this article, we will use the word "website" as the catch-all. But know that every single one of these 12 mistakes applies whether you are building a landing page or an enterprise application. We have seen them all, we have fixed them all, and the data behind each one is hard to argue with.

1. Navigation that makes users think

If someone lands on your site and has to stop and figure out where to go, you have already lost them. A 2022 study of 6,000 consumers found that 37% abandon a website because of bad navigation or poor layout. That is more than a third of your visitors gone before they have even seen what you offer.

Hick's Law tells us that decision time increases with every option you add. Cram 15 items into your main navigation and you are not giving people choice. You are giving them confusion. We see this constantly on audits: mega-menus with 40 links, duplicate labels, and the most important content buried three or four levels deep.

The fix is rarely about adding more. It is about being brave enough to take things away. Limit primary navigation to 5 to 7 items. Use clear, descriptive labels. "Solutions" means nothing. "Web apps" tells people exactly where they are going. Test your navigation with real users, not just your internal team.

What we found in the real world

We worked with a UK-based healthcare technology company on a platform redesign. On the surface, the component design was clean. But the navigation told a different story. Users hit dead ends where they expected options. Moving between action plans and improvement plans was confusing, and finding assigned tasks meant digging through multiple layers of the system.

We restructured the information architecture, brought buried content to the surface, created clear links between related sections, and introduced guided wizards that walked users through essential steps before opening up the full navigation. Support queries dropped, task completion rates improved, and assessment drop-off reduced significantly.

2. Mobile disasters that cost you more than you think

Over 62% of all web traffic now comes from mobile devices, and Google's mobile-first indexing means the mobile version of your site determines your search rankings. If your mobile experience is poor, you are invisible.

But here is the gap that should keep you awake at night. Desktop still converts at roughly 3.85% compared to mobile's 2.85%. That means desktop visitors are 1.7 times more likely to convert. With mobile accounting for the majority of your traffic, that conversion gap represents a huge amount of lost revenue.

We run mobile audits as part of every kwiboo project, and the issues are remarkably consistent. Tap targets too small. Text requiring pinching and zooming. Forms impossible to complete on a phone. These are not edge cases. They are the norm on sites designed desktop-first and squeezed onto a smaller screen as an afterthought.

Design mobile-first. Always. Start with the smallest screen and work upwards. Ensure tap targets are at least 44 by 44 pixels. Test every user journey on an actual phone, not a browser simulation. The difference is real.

What we found in the real world

We worked with a multinational electronics manufacturer on an application originally designed specifically for iPad. This was before responsive design had become standard practice. The problem came when the client expected it to work on phones and desktops. Layouts broke on smaller devices. The app was delivered via an iframe in their existing website, causing scroll traps and horizontal scrolling. On a phone, it was unusable.

We redesigned and rebuilt the application from scratch as a fully responsive solution. No iframes. No device-specific compromises. The experience went from broken to seamless.

3. Typography crimes that nobody notices (until they leave)

Typography is the invisible architecture of your site. A 2022 Monotype neuroscience study found that typeface choice alone can increase perceived trustworthiness by 9%. The minimum recommended body text size is 16px. WCAG requires a contrast ratio of at least 4.5:1 for normal text. The optimal line length is between 45 and 75 characters.

We have audited sites where the body text was light grey on white, the line height was set to 1.0, and three decorative fonts were fighting for attention on the same page. It looked "designed." It was unreadable.

Set body text to 16px minimum. Use a line height of 1.5 times your font size. Stick to two typefaces maximum. Check contrast with the WebAIM contrast checker. Small changes, measurable difference.

4. Forms that kill conversions one field at a time

Approximately 68% of people who start filling out a web form never finish it. The reasons are predictable: too long, too intrusive, or no clear explanation of why information is needed. Expedia removed a single optional "Company" field and gained 12 million dollars in additional annual profit. One field.

Audit every field. If you need more than 5 or 6 fields, break the form into steps. HubSpot data shows multi-step forms convert 86% higher than single-step designs. Add inline validation so people know immediately when something is wrong.

What we found in the real world

We worked with an online pharmacy whose consultation form was presented as one enormous page of questions. No conditional logic. No branching. Every patient saw the same questions in the same order. The moment users saw it, the reaction was predictable: "How long is this going to take?"

We replaced it with an intelligent, single-question-at-a-time flow. Each answer determined the next question, routing patients through the shortest possible path to their treatment options. The same clinical information was gathered. It just felt like a fraction of the work. Completion rates improved and patients reached treatment options faster.

5. Slow loading disguised as design choices

Google research shows that as page load time increases from 1 to 3 seconds, bounce probability rises by 32%. From 1 to 5 seconds, it jumps by 90%. The Deloitte "Milliseconds Make Millions" study found that a 0.1-second improvement in mobile load time increased retail conversions by 8.4% and average order values by 9.2%. A site loading in 1 second converts 3 times higher than a 5-second site.

We have walked into client meetings where the site takes 8 seconds to load and the first question is "why are our conversions so low?" The answer is staring at them, slowly, from a loading spinner.

Run your site through Google PageSpeed Insights and aim for a Largest Contentful Paint under 2.5 seconds. Compress images. Use modern formats like WebP. Lazy-load content below the fold. Question every third-party script. That analytics tag, that chat widget, that tracking pixel, they all add up.

What we found in the real world

We worked with a large consumer-facing platform where the performance problems were not caused by technical debt. They were caused by the relentless desire from management and marketing to make every element "more designed." Oversized hero sections. Heavy treatments and unnecessary animation.

The Lighthouse performance score was around 50 out of 100 on both desktop and mobile. We stripped things back, compressed every asset, removed elements that added visual weight but no user value, implemented critical CSS, and delayed off-screen loading. The score went from 50 to 100 on both desktop and mobile. Not 80. Not 90. A perfect 100.

6. Visual clutter that ignores how people actually read

Nielsen Norman Group's eye-tracking research shows that 79% of users scan rather than read online content. When a page is cluttered, users cannot scan effectively. Research from Human Factors International found that whitespace increases comprehension by almost 20%, and 75% of people judge a site's credibility based on visual design alone.

Give your content room to breathe. Use clear headings, short paragraphs, and enough whitespace to guide the eye. Each section should have one clear purpose and one clear action. If everything competes for attention, nothing wins.

7. Calls to action that nobody clicks

HubSpot analysed 330,000 calls to action and found that personalised CTAs convert 202% better than generic ones. Yet 70% of small business websites do not feature a call to action at all. ContentVerve found that first-person phrasing ("Start my free trial" versus "Start your free trial") increased click-through rates by 90%.

Every page needs a clear, visible call to action. Use first-person, action-oriented language. "Let us talk about your project" beats "Contact us." One primary action per page. Make it obvious.

8. Accessibility failures that exclude 16% of the population

The WebAIM Million 2025 report found that 94.8% of the top 1 million homepages had detectable accessibility failures, averaging 51 errors per page. The World Health Organisation reports that 1.3 billion people globally live with some form of disability. In the UK, the Equality Act 2010 requires service providers to make reasonable adjustments for disabled people, and that includes your website. Accessibility lawsuits are rising sharply, with over 4,000 filed in the US alone in 2024.

Start with the basics. Meaningful alt text on images. Colour contrast ratios that meet WCAG AA standards. Properly labelled form fields. Full keyboard navigation. Do not rely on accessibility overlay widgets. Build it in from the start.

What we found in the real world

We worked on a case management platform where the original colour scheme had been driven by aesthetic preferences rather than compliance. When the company began expanding into the US market, where digital accessibility lawsuits are routine, compliance became urgent.

Rather than forcing a complete rebrand, we created two additional fully compliant themes alongside the original. Users could switch themes based on their needs, with customisable elements for further personalisation. A pragmatic solution that respected the brand while ensuring nobody was excluded.

9. Auto-playing media and intrusive pop-ups

83% of users rate auto-playing videos as "very annoying." Few things destroy trust faster than a video blaring sound the moment a page loads, or a full-screen pop-up demanding an email address before the visitor has read a single word. Google penalises mobile pages with full-screen interstitials, and Nielsen Norman Group classifies exit-intent pop-ups as "needy design patterns" that damage credibility.

We understand the temptation. Pop-ups can capture email addresses. Auto-playing videos can increase time on page. But these are vanity metrics. What they actually do is erode trust and push away the exact people you want to attract.

Value first, ask second. Let people engage with your content before asking for anything. If you use a pop-up, trigger it after genuine engagement: after a user has scrolled 50% of the page or spent 30 seconds reading. Never auto-play video with sound. Respect your visitors and they will respect your brand.

10. Inconsistent design that quietly erodes trust

Jakob Nielsen's foundational UX principle is simple: users spend most of their time on other sites, so they expect yours to work the same way. When buttons change colour between pages, when spacing shifts, when the tone lurches from professional to casual, users notice. Maybe not consciously. But the trust drains away.

The Lucidpress State of Brand Consistency Report found that consistent branding can increase revenue by up to 33%. UX research shows inconsistent interfaces increase cognitive load by 47%, directly impacting how well people can complete tasks.

Build and maintain a design system. It does not have to be complex. At its simplest, it is a documented set of colours, fonts, spacing rules, and component patterns that every page follows. At kwiboo, we build design systems into every project because consistency is not about aesthetics. It is about trust. And trust converts.

11. Search that does not work

Site search users convert at nearly double the rate of browsers, and on some sites up to 6 times higher. Yet Baymard Institute reports that 72% of sites completely fail to meet search expectations. When search fails, 12% of users leave immediately for a competitor.

If your site has more than 50 pages or 20 products, you need search that works properly. Implement autocomplete, handle synonyms, and review your search analytics monthly. It is one of the quickest wins in conversion optimisation.

12. Launching and walking away

This might be the most costly mistake of all, and it is not really a design mistake. It is a mindset mistake. Too many businesses treat their website as a project with a start date and a finish date. Build it, launch it, move on.

McKinsey's Design Index study tracked 300 publicly listed companies over five years and found that top-performing design organisations achieved 32 percentage points higher revenue growth than their peers. Forrester reports that every £1 invested in UX returns £100. Jared Spool's famous "300 million dollar button" case study proved that changing a single word on a form button generated 300 million dollars in additional annual revenue. Yet more than 40% of companies do not talk to their end users during development.

Treat your website as a product, not a project. Set up analytics properly. Watch how real users behave. Run A/B tests on your most important pages. Review your data monthly and make improvements based on what you find. The businesses that win online are not the ones with the biggest launch budgets. They are the ones that never stop improving.

What we found in the real world

Our work with Mitsubishi Electric on their Ecodan product range is the best example we have of continuous improvement in practice. We have been working with them for over 10 years, and the Ecodan Selection Tool and Find My Ecodan applications are now in their third major iteration.

Each version was informed by the last. What we learned from version one shaped version two. What users and installers told us through version two shaped version three. The applications evolved to work seamlessly across desktop, mobile, and large-format touchscreens used at trade shows like the Installer Show and the Ideal Home Show.

The results speak for themselves. The tools have driven increased sales leads, expanded into wider use across the business, and reached audiences in contexts we never originally designed for. Most importantly, the success of these applications led other departments within Mitsubishi Electric to come to kwiboo for entirely different projects. That is what happens when you treat a digital product as something that grows and improves over time rather than something you launch and forget. The returns compound. The relationship deepens. And the results keep getting better.

These mistakes compound. The fix does not have to.

None of these 12 mistakes exist in isolation. A slow site with bad navigation, poor mobile experience, and inaccessible contrast does not lose users at one point. It loses them at every stage. The damage compounds quietly, visit after visit, until the site is underperforming so badly that a complete rebuild feels like the only option.

But the fixes compound too. Removing one form field can be worth millions. Shaving a tenth of a second off your load time lifts conversions by 8.4%. Personalising a CTA triples its effectiveness. These are not theoretical improvements. They are proven, measurable changes we have delivered for clients across industries.

Whether you call it a website, a web app, or a SaaS platform, the principles are the same. Reduce friction. Respect your users. Test everything. Keep improving.

And if any of these 12 mistakes sound familiar, that is not a problem. That is an opportunity.

Think your site might be making some of these mistakes?

We have been fixing bad website design for over 20 years. Let us talk and turn your next big idea into a reality. Get in touch.