I've quit a few jobs because I've gotten bored or because it restricted my free time severely. I quit a shitty job that paid top dollar AND had mandotory overtime so I made ridiculously more - however, I was working 6am to 5pm-7pm SEVEN days a week, with 1 day off every 2 weeks. My life was literally, working, sleeping and eating. The crazy hours wouldn't last long, but I couldn't wait, so I quit. I have no regrets. When I gave them a two week notice, I immediately felt relieved and noticeably happier.
This past Friday I informed my second part time job at a bar that I was getting bored and pulling so much more weight than the employees getting paid the same as I. Other employees would literally come to me for guidance or instruction, the owner himself would put me in charge of an entire floor and have me report to him etc.. I was basically being used. I told them that I'll be gone in two weeks, they both the owner and the general manager immediately offer me a better position and/or more money in the same position, we plan to "figure something out" this week. I don't know what they have in mind, but I warned them it would take a significant pay increase to stay, so I'm not getting my hopes up. I was happy that they acknowledged all the work I was doing, I didn't think they noticed. Now that I know they did notice, why wasn't I offered a raise??!
Anyway, I think the point I'm trying to make is do what makes you happy AND what you can reasonably do. I'm lucky enough to have a decent amount saved up and can easily go months without working. If I did not have what I do in my savings (or if I had kids, a lot of debt etc..), I probably wouldn't have made the same decisions I mentioned above.
So in short, life is short, do what makes you happy that won't make you miserable in the future.