George: Excuse me, I gave you a twenty dollar bill and you only actually gave me change for a ten.
Cashier: You gave me a ten.
George: I'm positive I gave you a twenty.
Cashier: I know what you gave me.
George: You owe me ten dollars.
Cashier: Will you please step aside? Next?
George: All right, let's just examine the situation for a second. Who, in this situation, would be more likely to make a mistake? Me, who had access to my wallet, knew exactly what was in there? Or you--
Cashier: You.
George: No, no, no. See you're not really listening.