I'm sure we've all had humor arising from the out of character vs in character divide. It's always great when your dwarf fighter declares that they wish they had an uzi. Uzi? What is this uzi you speak of comes the cry from the rest of the table. Thus begins the merriment. I've heard at some tables you have to hold your hands up on your heads like moose antlers to indicate you are speaking out of character. This is all to avoid confusion you see. Nothing to do with making everyone look like they're completely insane. Or to amuse the heck out of everyone else. Nope. Not at all.
Art from GIS for D&D humor and probably penny arcade as well