There was once an accounting firm where the senior CPA knew every thing there was to know about accounting. He could answer any question. He knew all the tax laws: There wasn't a better accountant anywhere.
Every morning when he came to work, he would unlock his desk drawer, open it up and look inside for a minute, and then close and lock it again.
This puzzled all of his co-workers, because it was the only eccentricity that this person exhibited. They tried many times to look over his shoulder, or get into his desk when he wasn't there, without success.
One day when the elderly man was sitting at his desk, going over an account, he suffered a heart attack and died. This upset everyone tremendously. However, now that he was gone, the other members of the firm could finally see what was in the drawer.
After obtaining the keys, they unlocked the desk drawer and cautiously peeked inside. They found one sheet of paper, and written in large letters was:
DEBITS ON THE LEFT...CREDITS ON THE RIGHT