A general noticed one of his soldiers
behaving oddly. The soldier would pick
up any piece of paper he found, frown
and say, "That's not it" and put it
down again.

This went on for some time, until the
general arranged to have the soldier
psychologically tested.

The psychologist concluded that the soldier
was deranged, and wrote out his
discharge from the army.

The soldier picked it up,
smiled and said, "That's it."