以前のブログに乗っけていたやつです。
During a visit to the mental asylum, a visitor asked the director,
"What is the criterion that defines a patient to be institutionalized?"
"Well..." said the director,
"we fill up a bathtub, and we offer a teaspoon, a teacup, and a bucket to the patient and ask him to empty the bathtub."
"Oh, I understand," said the visitor.
"A normal person would choose the bucket as it is larger than the spoon or the teacup."
"Noooooooo!" answered the director.
"A normal person would pull the plug."
(You are not required to tell anyone how you would have done on this test.)