You have to work on something you are passionate about. If you work on Sundays because you cant keep yourself away from it, then great. If you work Sundays because you think if you work hard enough you will become rich and successful, then you are likely going to burn yourself out. Your life is NOW, be happy now. Don't push it off. If coding all day makes you happy do so. but if you rather hang out at the beach do so. There is nothing wrong with that.

I see a lot of startups made up of people who bought in to the startup myth and all they want to do is be successful. They dont care the least about the problem they are trying to solve, or like to do the work needed to solve it. If you would spend day and night on something even if you knew it would never come to anything, then that's the thing you should do.

A lot of people try to figure out what the pattern for the perfect startup is, and I think its just what ever you are passionate about. Maybe it will work out, maybe it wont, but at least you wont have wasted your time.

If you are passionate about caviar, be a sturgeon fisherman, or a chef. dont start a startup.