It depends on how you value your time and effort. Not every idea should be valued by its market fit. I don't think people should write code they are uninterested in writing. That's my litmus test for myself. Usually when I'm really, really interested the thing I'm aiming at doing initially isn't even about what I'm really trying to solve. It's picking away at the cruft over something and then I can see what's on the other side. Don't write things from scratch if you absolutely hate it and you are only doing it because you think the market will buy it and you wanna be a big biz, unless you feel like it. I don't know, YMMV. Programming is stupid and I plan to be a pig farmer as soon as possible.