Joke or not: how to determine if one is "fit" for the loony bin

It's call the Bathtub test:
During a visit to the mental hospital, I asked the Director 'How do you determine whether or not a patient should be admitted to the hospital.'

'Well,' said the Director, 'We fill up a bathtub, and then we give a teaspoon, a teacup and a bucket to the patient and ask him to empty the bathtub.'

'Oh, I understand,' I said. 'A normal person would use the bucket because it's bigger than the spoon or the teacup.'

'No.' Said the Director, 'A normal person would pull the drain plug.

Well... Would you prefer a bed near the window?'