Contentment

 As human beings, we strive to achieve various goals and think "if I just manage to get that thing," or "If I just accomplish that, then I'd be happy." But when we get what we were striving for, it's never enough. There's always another goal on the horizon. 

I've been laboring under the impression that if I just got famous, or got a girlfriend or both, I'd be happy. But now that I think about it, I'd probably be looking for something else after that. That's why people who make big movies feel compelled to keep making more, even though they don't need to. It didn't make them complete or happy enough.