Sometimes I wonder if greatness comes at the price of a continual dissatisfaction. There's the old story of how Beethoven - I somehow suspect it was actually Tchaikovsky, but these emo-tragedy stories seem to fit Beethoven's hairdo so much better - had insomnia after a concert, saying that "the music won't leave my head!" Of course it could have been, "it should have been Moses instead" but somehow I doubt it.
It does seem that the ones who make it beyond a certain level not only have a certain kind of drive or work ethic - but a strange sort of motivation that underlies that momentum. Many of us are happy to push ourselves to reap the benefits of our efforts, but some people drive forward simply because of a perfectionist dissatisfaction that it's never good enough. Even if it's good enough for everyone else, it's not good enough for them. Occasionally you'll get someone with her head screwed on right like Midori, who, in a CNN interview said that one must realize and accept that it'll never be perfect - this, from one of the few who are said to be as consistent on stage as in recordings.
Still, one has to admire what dissatisfaction can accomplish, in a sense. Even if the actual life - insomnia and all - is hardly what we might choose for oneself. As if it were ever a choice, and not a calling.