From the recent Oliver Burkeman interview with Woody Allen in the Guardian - he says it wonderfully about the doubt that assails anyone involved in the creative process:

“I have an idea for a story, and I think to myself, my God, this is a combination of Eugene O’Neill, and Tennessee Williams, and Arthur Miller... but that’s because when you’re writing you don’t have to face the test of reality. You’re at home, in your house, it’s all in your mind. Now, when it’s almost over, and I see what I’ve got, I start to think: what have I done? This is going to be such an embarrassment! Can I salvage it? All your grandiose ideas go out the window. You realise you made a catastrophe, and you think: what if I put the last scene first, drop this character, put in narration?”

These fusillades of self-criticism, you sense, aren’t false modesty, nor real terror, but something else: the musings of a veteran who has long since come to terms with the fact that his creative process will always be a long slide into disillusionment. Nine times out of ten, he says, when he leaves the screening room of the first rough cut: “The feeling is: OK, now don’t panic.” The other 10% of the time, it’s “OK. That’s not as bad as I thought.”