The fact that David Letterman lives in a society that puts a great premium, puts a great value, on a certain type of smirky joke, that's not his doing. He's lucky that he happens to live in such a society.
Then my brother walks in with his smirky grin and he says to me, " What's wrong with you? " I said, " Nothing, just leave me alone." And he did, he ran as fast as he could.