Yesterday, All My Combos Seemed So Far Away…

(It is my second day: An old customer comes in and rattles off a long combo order. Still getting used to the registers, I hit a wrong key, which causes the price to register without the combo discount.)

Me: “Okay, your total is [amount].”

Old Customer: “NO, it is NOT! It should be [different amount]. You did the same thing to me last week!”

Me: “…I just started yesterday, sir.”