7 common UI/UX design mistakes to avoid

UI/UX design is constantly evolving. Delivering a smooth, intuitive and high-performing user experience has become a key challenge for companies that build digital tools. Yet some design mistakes keep coming up, hurting readability, conversion and customer satisfaction.

At Fragments Studio, we have worked on many web, SaaS and business tool projects. Here are the 7 most common UI/UX mistakes we come across and how to avoid them.

1. Ignoring user research

User research is one of the most important steps of the "discovery" process. Many companies skip this phase for lack of time or budget, but it is a major mistake. Designing a product without understanding your users' needs and expectations is like designing a house without planning the foundations.

Why it is a problem: You risk designing useless features or neglecting essential needs, which can frustrate your users.

Best practices: Take the time to run user interviews, surveys and user behavior tests to gather valuable insights. At Fragments Studio, we use tools like PostHog and Google Analytics to analyze behavior and focus on the core of the need, so we can quickly deliver an iterative prototype.

2. Too much information on a single page: the enemy of readability

An overloaded design is a common mistake, especially when you want to impress or show off every available feature. However, too much information on a page can easily overwhelm the user.

Why it is a problem: Users do not know where to look and may leave the page without finding what they are looking for.

Best practices: Apply the "Less is more" principle. Simplify your interfaces and prioritize information. Do not use more than two or three main colors, and favor white space to let the page breathe.

3. Inconsistent design: confusion and frustration

Inconsistency in design is one of the most common mistakes and one of the most harmful to the user experience. This includes changes in styles, fonts or colors from one page to another, for no apparent reason.

Why it is a problem: The user has to keep adapting, which increases cognitive load and creates confusion.

Best practices: Use a design system. Today we build design systems to guarantee visual and functional consistency for our clients, across all types of devices. Having a design system makes the product easier to maintain and evolve.

4. Neglecting user testing: there is no such thing as a perfect design

Many web/UX/UI designers think their work is done once the mockup is approved. But design should always be tested with real users before going into production.

Why it is a problem: You risk discovering usability issues after launch, which can be costly to fix.

Best practices: Include user testing sessions from the prototyping stage onward and iterate based on feedback. A/B tests are also useful to compare different versions and identify the one that works best; it is a practice we use almost systematically when delivering our projects.

5. Forgetting accessibility: excluding part of your audience

Designing without taking accessibility into account is a mistake that can exclude a large number of users. About 15% of the world's population lives with a disability, and failing to adapt your interfaces to their needs can damage your reputation.

Why it is a problem: You limit access to your product and create a frustrating experience for users with visual, hearing or motor impairments.

Best practices: Apply the WCAG (Web Content Accessibility Guidelines). Use sufficient contrast, add descriptions to images (alt text), and make sure all content is accessible to everyone.

*Optimizing the accessibility of your website also optimizes your SEO.

6. Using too many animations and interactions: the experience trap

Animations and interactions can improve the user experience, but overusing them can quickly become counterproductive. Websites and applications overloaded with visual effects are often considered experiential sites; this type of site must be designed for very specific goals and use cases.

Why it is a problem: Beyond performance and loading issues, the real danger is losing the user's attention. Too many visual effects can easily distract users and draw their eyes away from the important information. The difference between an interactive site that impresses and a site that tires the user is sometimes very subtle.

Best practices: Be selective in your use of animations. Make sure they serve a specific purpose, such as guiding the user or giving visual feedback. At Fragments Studio, we integrate subtle micro-interactions to enrich the experience without hurting readability.

7. Not optimizing for mobile: an obligation?

In 2024, the majority of users access digital tools and websites on mobile (over 95%). Neglecting mobile optimization is a mistake that can be costly in terms of conversion and user experience.

Why it is a problem: An interface that is not optimized for mobile makes navigation difficult, discourages users and limits accessibility.

Note: Not every tool and website needs a mobile version. In some cases, especially for specialized business tools, most users connect exclusively from a computer. A mobile version would then be neither useful nor necessary. Optimizing for desktop only lets you focus on a better-suited, higher-performing experience, directly meeting users' needs without adding unnecessary complexity.

Best practices: Adopt a mobile-first approach in your designs. Test your interfaces on different devices and screen sizes to guarantee a smooth experience everywhere.

Conclusion: avoid common mistakes and improve your designs with Fragments Studio

Avoiding these common UI/UX mistakes can transform your products and deliver a much more pleasant and effective user experience. The goal is to focus on research, accessibility and user testing to design intuitive, consistent interfaces that meet your real needs.

Want to improve the user experience of your digital product? At Fragments Studio, we design clear, consistent and accessible interfaces, with a method centered on your real users. 👉 Let's talk about your UX/UI challenges

Bonus - Questions related to this article:

What mistakes should you avoid in UX design? The most common mistakes include a lack of user research, a lack of visual hierarchy, inaccessible interfaces and inconsistent design.

Why is web accessibility important for the user experience? Accessibility ensures that all users, including people with disabilities, can navigate easily. It is also a lever to improve your SEO.

My site has no mobile version: is that a problem? It all depends on your audience. For business tools used exclusively on desktop, it is not a blocker. But in 95% of cases, a mobile version is essential for the user experience.