You walk to your car, looking for anything you can pass off as his order. You manage to find an empty box of roughly the right size, but it is labeled with a postal service decal and a stamp reading "FIRST CLASS PAID," but maybe he won't notice those things.
"Here you go," you say as you present the empty box and hold your hand out for a tip.
"Uh," he begins, "really? I'm not an idiot, you know; I can tell an empty package from a box of breadsticks."
Oh no! The jig is up! You run away crying, ashamed of your deception and ashamed of your performance as a delivery person. You wake up wishing you'd never even made that damned pizza.