I once heard someone introduce an author as someone who "writes for the pleasure of discovering what he thinks." I thought that was a beautiful way to sum up what the writing process is all about. It's not all pleasure of course, but I find that astounding personal growth—and the satisfaction of having grown—is often as much a product of writing as the written piece itself.
Today I turn to writing because I long to feel better. I hope the critical thinking that writing requires will help me grow and feel better, even if just a little. Also, I find that having to extract thoughts from my own head and say them "out loud" sometimes demystifies them. Things that seem so important and true within the labyrinth of my mind are often exposed for the folly they are when I bring them out for show and tell. I recently learned a beautiful line from the play Macbeth. As Macbeth ponders his wish to kill the king and gain the throne for himself, he says "Stars, hide your fires! Let not light see my black and deep desires." Only I desire the opposite: I want to bring my darkest fears and weaknesses out of myself so that they whither in light-saturated reality.