If I quoted every little thing he said which rang a bell for me this post would be half again as long as the interview itself. So I'm going to limit myself to just a couple, but I strongly encourage you to take a few minutes and go read the whole thing.
Self-expression is a hallmark of an artist, of art, to get something off one’s chest, to sing one’s song. So that element is present in all art. And comedy, although it is not one of the fine arts—it’s a vulgar art, it’s one of the people’s arts, it’s the spoken word, the writing that goes into it is an art form—it’s certainly artistry. So self-expression is the key to even standing up and saying, "Hey, listen to me." Self-expression can be based on looking at the world and making observations about it or not. Comedy can also be based on describing one’s inner self—doing anecdotes, talking about your own fears...But I don’t think these things are mutually exclusive. I think self-expression is present at all times, and whether or not you’re talking about the outside world or your responses to it depends on the moment and the subject.
The writing is what gives me the joy, especially editing myself for the page, and getting something ready to show to the editors, and then to have a first draft and get it back and work to fix it, I love reworking, I love editing, love love love revision, revision, revision, revision.
Interview found via Mark Evanier, who was told about it by another one of his readers, Dawna Kaufmann.