Bad idea: Calling the pregnant woman at work "fatso," and then saying "I'm sorry, do you need a hug? No? Good, because I don't think my arms will fit."
It was one of those things where you had to be there to appreciate it, but I know her enough to feel pretty safe about saying those things. Her sense of humor is almost as self-deprecating as mine, and she went around telling everybody about our conversation because she thought it was funny. In fact, when somebody tried to sympathize with her and told her that I'm mean, she said "Pfft. It's hilarious."
Know who didn't think it was hilarious? The unusually difficult-to-offend girl who's always asking if I saw last night's episode of South Park and who once equipped a Jesus action figure with Power Rangers accessories. Apparently the fat issue strikes a nerve with her. I may never hear the end of it.