A veterinarian was feeling ill and went to see her doctor. The doctor asked her all the usual questions: What are your symptoms? How long have they been occurring? Etcetera. Finally the vet interrupted the doctor, saying, "Hey look, I'm a vet -- I don't need to ask my patients these kind of questions; I can tell what's wrong just by looking. Why can't you?"
The doctor nodded, looked her up and down, wrote out a prescription and handed it to her and said, "There you are. Of course, if that doesn't work, we'll have to have you put down."