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.
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