The easiest way to get people to stop using your product is for it to not work, or for them to not figure out how to use it.
User interface is not just about how a product looks. It is the entire appearance and feel of an app or website — including the structure of each screen and the relationships between components. A good UI guides users effortlessly through your product, making it intuitive, consistent, and clear.
The trap is treating UI as decoration or a checklist of features. The actual job is to design interfaces that users understand and want to use repeatedly. If users cannot find what they need or get confused about what happens when they interact, they leave.
This lesson teaches you how to think about UI through real design principles and user psychology, so you can answer the interview question: How do you define a good user interface?
UI is the gateway to user experience
User experience (UX) and user interface (UI) are often confused but are distinct. UX is the overall attitude or reaction a user has toward your product — their emotions, perceptions, and satisfaction. UI is the tangible layer where users interact — buttons, layouts, typography, navigation.
Talvinder calls UI the "entire appearance and feel" — it is what users see and touch. UX is the psychology and behavior that result from that interface.
A product with great UX but poor UI will frustrate users. A product with great UI but poor UX might look good but fail to solve the user's problem.
India Mart is a good example. Its UI is business-focused, clear, and concise, prioritizing the business user’s needs. The design is not flashy but functional — this clarity supports a strong UX for its target audience.
Product design review at an Indian B2B marketplace startup
Design Lead: “The homepage feels cluttered. Users complain they can’t find product categories quickly.”
PM: “What’s the core action we want users to take? Should we simplify navigation to just 3 main categories?”
CEO: “I want to showcase all our offerings upfront. More choices mean more sales.”
PM: “More choices can cause paralysis. Our user research shows users want speed and clarity over options.”
The team agrees to prototype a simplified UI focusing on the top 3 categories.
Balancing business goals with user clarity
The psychology behind UI design
Good UI design is grounded in understanding user behavior and cognitive limits. Users do not read every word; they scan. They form expectations based on conventions. They prefer consistency and predictable interactions.
Talvinder summarizes six components of user experience that link to UI:
- Credible: Users trust the interface to behave as expected.
- Findable: Users can locate what they need quickly.
- Usable: The interface is easy to use, with clear affordances.
- Useful: The interface supports tasks users care about.
- Desirable: The design delights and motivates users to return.
- Accessible: The interface works for users with diverse abilities.
These components show that UI is not just about looks. It is about shaping user behavior and trust.
For example, a button labeled "Submit" that is greyed out until a form is valid signals system status and guides action. A confusing layout with inconsistent button styles breaks credibility and usability.
Dieter Rams’ principles for good product design
When asked in an interview, Talvinder recommends referencing Dieter Rams’ ten principles of good design. These apply to UI as well:
- Innovative
- Makes a product useful
- Aesthetic
- Understandable
- Unobtrusive
- Honest
- Long-lasting
- Thorough down to the last detail
- Environmentally friendly
- Involves as little design as possible
The last point is crucial: minimalism is not just style but a value. Every design element must have a purpose. Excessive decoration or complexity distracts users and hides functionality.
Practical criteria for good UI
To evaluate a UI, focus on these practical points grounded in Talvinder’s teaching:
- Simple user navigation: Can users move through screens intuitively? Are menus clear and logically grouped?
- Well-defined target audience: Is the UI tailored to the users’ skills, preferences, and goals?
- Consistency: Do similar elements behave the same way across the product? Is typography, color, and layout uniform?
- Transparency of user actions: Do users understand what happens when they click? Are feedback and system status visible?
- Hierarchical order of screens: Is the UI structured to guide users from high-level overview to detailed actions without confusion?
These criteria help you judge if the UI supports the user’s mental model and goals.
Measuring UI effectiveness
Measuring UI is essential to avoid guesswork. Talvinder emphasizes metrics that reveal whether users find and use features as intended:
- Frequency of back button usage: High rates indicate users cannot find what they want.
- Time on task: How long it takes users to complete key flows.
- Error rates: How often users make mistakes due to UI confusion.
- Feature adoption: Whether users discover and regularly use new UI elements.
User behavior analytics combined with qualitative feedback (surveys, interviews) reveal UI strengths and weaknesses.
India’s diverse user base also requires testing UI on different devices, languages, and literacy levels. A UI that works well for metro users may fail in tier-2 or tier-3 cities if it is not accessible or localized.
Field exercise: Evaluate your favorite app’s UI
Pick an app you use daily — Swiggy, PhonePe, Razorpay, or any.
- Identify the core user flows (placing an order, making a payment).
- For each flow, note:
- How easy is navigation? Are buttons and links clear?
- Is the design consistent across screens?
- How transparent are user actions? Do you get immediate feedback?
- Rate the UI on a scale of 1 to 5 for:
- Simplicity
- Consistency
- Clarity
- Delight
- Suggest 2 improvements based on your observations.
Share your findings with a peer or mentor to discuss different perspectives.
UI vs UX: What every PM must know
Talvinder tells PMs: Your job is to own the user experience, not just the UI. UI is a tool to shape UX, but UX includes everything from onboarding, customer support, to performance.
For example, a beautiful UI that loads slowly or crashes destroys UX. Conversely, a plain UI with fast, reliable features can create a great UX.
Indian startups like Meesho and Zerodha focus heavily on simple, fast UIs that perform well even on low-end devices and slow networks — critical for their user base.
Knowing this difference helps you prioritize engineering and design efforts for maximum impact.
Interview scenario: Defining a good UI
You are interviewing for a PM role at a fintech startup in Bangalore. The interviewer asks: 'How do you define a good user interface?'
The call: What is your best response to demonstrate design sense and product intuition?
Your reasoning:
You are interviewing for a PM role at a fintech startup in Bangalore. The interviewer asks: 'How do you define a good user interface?'
Your task: What is your best response to demonstrate design sense and product intuition?
your reasoning:
From the field: Why UI matters more than you think
The UI design challenge in India
Designing UI for the Indian market means facing diverse languages, literacy levels, and device capabilities. A UI that works on a high-end smartphone in Mumbai might fail on a low-cost device in a rural area.
Indian companies like Swiggy and PhonePe invest heavily in localization, offline modes, and simplified flows. For example, using iconography and minimal text helps non-English speakers.
As a PM, you must push your design and engineering teams to test across these realities and not assume a one-size-fits-all UI.
Where to go next
- Deepen your understanding of user research: User Research Methods
- Learn how to translate UI into UX strategy: Product Vision and Strategy
- Master measuring product impact: Metrics and KPIs
- Explore accessibility best practices: Inclusive Design
- Understand ethical design principles: Ethical PM
PL alumni now work at Flipkart, Razorpay, Swiggy, PhonePe, Amazon, Microsoft, and 30+ other companies.