I used to pick side projects based on all the things they say you should; does it have a large addressable market, does it solve customer pain points, are people willing to prepay before you start working on it etc. And I would get to a point where I would give up because the projects, chosen this way, were not fun anymore and I would stop working on them.

So instead I now pick things that I find to be fun to me to work on. Instead of solving customer pain points, I try and solve a pain point that I have. I'm liking it thus far