First, let me state my credentials: I am a funny guy. This is well known in certain circles, which is why, even back in elementary school, I was sometimes asked by the teacher to "say something funny" -- as if the deed could be done on demand. This, anyway, is my standing for stating that Stephen Colbert was not funny at the White House Correspondents' Association Dinner. All the rest is commentary.
The commentary, though, is also what I do, and it will make the point that Colbert was not just a failure as a comedian but rude. Rude is not the same as brash. It is not the same as brassy. It is not the same as gutsy or thinking outside the box. Rudeness means taking advantage of the other person's sense of decorum or tradition or civility that keeps that other person from striking back or, worse, rising in a huff and leaving. The other night, that person was George W. Bush.