Doctors of old times tested the sanity of a mental patients with the following test:
The patient was placed in a room with a sink. The faucet was turned on and a stopper was put in the drain until the sink overflowed. The patient was then handed a mop and the door was closed.
If the patient had enough sense to shut off the water, pull the plug, and then mop up the water, he was considered capable of going home. But on the other hand, if the patient mopped like crazy
...