A customer moves away from a bank window,
counts his change, and then goes back and says to
the cashier, "Hey, you gave me the wrong change!"
           "Sir, you stepped away from the counter,"
said the cashier. "We don't make corrections after
you leave. There's nothing I can do about it now.
That's the policy of this bank."
           "Well, ok," answered the customer. "Just
thought you'd like to know that you gave me an
extra twenty. Bye."