Why Is Lying Harmful?

When a certain worker got too much money in his paycheck, he said nothing, thinking that he had indeed encountered some good luck.  The comptroller, however, found his mistake and deducted the overpayment from the next check.  This time, however, the worker loudly complained, "You made a mistake; you didn't pay me enough money."  The comptroller said, "Look, last pay check, I overpaid you, and you didn't say anything then.  Now, why do you complain when I deducted the amount of the overpayment?"  Embarrassed, the worker began to blush and replied, "Look, I can overlook one mistake, but with two mistakes I had to say something."