Sleep Owl, our iOS sleep tracking app, taught us more about product development than any project before it. The biggest mistake we made early on was designing for ourselves instead of our users. We packed the initial version with data — sleep cycles, REM breakdowns, heart rate overlays — because we thought more information meant more value. What we found instead was that most users opened the app, felt overwhelmed, and closed it. Data without context is noise.
The fix was radical simplification. We rebuilt the main screen around a single insight: "Here's how you slept last night, and here's one thing you can do better tonight." Everything else moved behind a tap. Retention improved significantly after that change. The lesson applies to any product: clarity beats comprehensiveness every time. Users don't want all the information — they want the right information, presented at the right moment.