Buddhism teaches that to attain happiness you have to accept the world as it is. (My knowledge of comparative religion was all picked up in the gutter, so forgive it please if I'm far from the mark.) The reverse, or obverse, or converse, or second verse same as the first, is that if you aren't changing anything (and thus are accepting the world as it is) then you must be happy. This seems to describe me to a T. I don't seem happy. I don't feel happy. But I'm not changing anything, so I must by definition be happy. Zen as all hell, don't you think?
Then again, it may be that not having a fire in the belly just means that you don't have a fire in the belly. I've never been hungry, not literally, but I've never gone hungry in the sense of having no food and no money for food. Decades of three squares a day may be why I'm down with keeping the status quo and expecting decades more of three squares a day. Not that Bill Gates or Steve Jobs were ever starving. I guess the roots of ambition are hard to root out or elucidate, but the roots of no ambition are maybe easier. Or maybe the puppeteer has just gotten bored and removed the hand from my back. Who knows?