We shipped a feature I was sure people wanted, and it landed with a shrug. Turns out I'd built it off my own hunch instead of actually asking anyone. Now I'm looking at weeks of work almost nobody uses, and I can feel it happening again with the next thing.
More people experience this than they realize.
You build from your own guesses instead of finding out what users actually need.
If this sounds familiar, the Library can help you find the bigger picture.