Via Calling in Life (advice to a young banker) :

What Wall Street did so well, for so long, was to give people jobs that they could pass off to themselves as well as others as callings. Such was their exalted social and financial status: Wall Street jobs made people feel special without actually having to be special. You never really had to explain why you were doing it – even if you should have. But really, the same rule that applies to properly functioning financial markets applies to other markets: There’s a direct relationship between risk and reward. A fantastically rewarding career usually requires you to take fantastic risks. To get your seat at the table on Wall Street you may have passed through a fine filter, but you took no real risk. You were just being paid, briefly, as if you had. So which is it: job or calling? You can answer the question directly, or allow time to answer it for you. Either way, I think you’d be happier if you stopped thinking of what the world had to offer you, and started thinking a bit more about what you had to offer the world. Real excitement isn’t just in whatever you happen to be doing, but in what you bring to it.

In the end, you have to look for it not on the outside, but on the inside. In my experience, if you find it, the other stuff will take care of itself.