(I have just finished ringing up a small order for a man and his 20-year-old son. Their change is only three cents, and they have already started walking away before I could hand it to them.)

Me: “Wait, I’ve still got your change, unless you don’t want it.”

Customer’s son: *doing Jedi hand wave* “We want our change.”

Me: *at the same time* “You don’t want your change.”

(We both wait a beat, then everyone in line breaks out laughing. We hadn’t practiced it, either.)