Dr. Cox: Newbie, do you happen to know what a zebra is?
J.D.: That patient just mocked me.
Dr. Cox: It's a diagnosis of a ridiculously obscure disease when it's much more likely that the patient has a common illness presenting with uncommon symptoms. In other words, if you hear hoof beats, you just go ahead and think horsies, not zebras. Mm-kay, Mr. Silly Bear?