It wasn't for nothing
Feels good seeing so many people feel the same way.  I've been working on an algorithmic trading project for a few years now and at times there have been speedbumps where I ask myself what I'm doing when I could be getting a lot more sleep or doing other hobbies like fishing, golfing, riding MTB, etc...I would add that little wins here and there are extremely motivating to keep pushing.  For example, I recently started digging back into trigonometry after many years of being away.  It's been extremely satisfying re-learning basic trig functions for an actual purpose, rather than simply solving a math problem.