Hmmm... I didn't really get the joke in the comic by itself. And now that I've heard the description of the humor, I still don't know as I would think it's funny. Guess I'd have to *see* it as opposed to hear about it.
One other point is that it's always confusing when you force the character on the right to speak before the character on the left. It's not how english speaking people are wired to read things.