Mr. Evans was the Chief Accountant of a large manufacturing company. Every day, on arriving at work, he would unlock the top drawer of his desk, peer at something inside, then close and lock the drawer. He had done this for 25 years.

The entire staff was intrigued but no one was game to ask him what was in the drawer. Finally the time came for Mr. Evans to retire. There was a farewell party with speeches and a presentation.

As soon as Mr. Evans had left the building some of the staff rushed into his office, unlocked the top drawer and peered in. Taped to the bottom of the drawer was a sheet of paper.

It read, "Debits on the left, credits on the right."