Woody, in the current issue of Esquire:

What people who don’t write don’t understand is that they think you make up the line consciously — but you don’t. It proceeds from your unconscious. So it’s the same surprise to you when it emerges as it is to the audience when the comic says it. I don’t think of the joke and then say it. I say it and then realize what I’ve said. And I laugh at it, because I’m hearing it for the first time myself.

I never see a frame of anything I’ve done after I’ve done it. I don’t even remember what’s in the films. And if I’m on the treadmill and I’m surfing the channels and suddenly Manhattan or some other picture comes on, I go right past it. If I saw Manhattan again, I would only see the worst. I would say: “Oh, God, this is so embarrassing. I could have done this. I should have done that.” So I spare myself.

In the shower, with the hot water coming down, you’ve left the real world behind, and very frequently things open up for you. It’s the change of venue, the unblocking the attempt to force the ideas that’s crippling you when you’re trying to write.