The best personal projects are the ones that solve your own problems. Not because they're guaranteed to find an audience, but because you're the most motivated person to finish them.

I built Bills Generator because I was tired of opening a spreadsheet every time I wanted to check whether I'd paid something. Nobody asked me to build it. Nobody is waiting for it. But I know exactly what it needs to do because I'm the user.

There's something clarifying about that. No requirements doc. No stakeholder meeting. Just a problem I had and a solution I wanted to exist.