A woman went to see a Doctor, complaining of an upset stomach.
The Doctor asked "What did you have for dinner last night?"
"Oysters," she replied.
"Were the oysters fresh?" asked the doctor.
"How should I know?" said the lady.
"Well," asked the doctor, "couldn't you tell when you took off the shells?"
"Oh my god," gasped the lady. "Are you supposed to take off the shells?"