The first ten users
The first ten users show what is real. I listen to what they do, not only what they say. I remove distractions. I make the best path the fastest path. I write down what worked and what did not. I repeat that loop until we see steady use.
Early users tell you what matters. They show you where confusion lives. They vote with their time.
If you build for everyone, you build for no one. Start narrow. Make ten people love it. Then scale what works.