The most common reason products fail is not bad technology or poor execution. It is that the builder never deeply understood the person they were building for. They assumed. They guessed. They built what they would want if they were the user — without ever checking whether the actual user wanted the same thing. User-centred design starts with one rule: do not guess what people need. Go and find out. Sit with someone who has the problem. Watch how they work around it. Ask what frustrates them, not what they want. People are often unable to describe what they want in advance — but they can tell you exactly what is not working right now. That is where you start.