Mental problems. I jest not. All (financially) successful people I know have serious mental problems. It's that special little fire in the belly that keeps you warm all those hard, lonely nights until you make it. Plus the extra voices in your head keep you company late at night. Oh and sexual frustration. Sublimation is a powerful tool if used properly. How many sexually satisfied folks with hot girlfriends who tend to their needs regularly do you know who are part of startups? None? Think about it. Your startup is your mistress. And professionalism. The ability to wait until after you've hit the jackpot to write that article about what a jackass your partner is, but to use the tension as fuel until you do so. Delusions of grandeur helps.