I recognize this as well. After a few side projects running out of interests from my side, while still liked but my early users, I also started to question why.

I recognize this as well. After a few side projects running out of interests from my side, while still liked but my early users, I also started to question why. I found the biggest motivator is user feedback. Especially positive ones.. It makes me stay up late to get another thing implemented or fixed etc. If I would run out of encouragement from users or people around me for a while, I think that is when I lose interest.