Whatever happens, keep it together
If you do notice you’ve been cheated on your grocery bill, accidentally or not, don’t lose your temper. First of all, the clerk behind the cash register isn’t probably authorized to give you your money back. If you’re throwing a fit, the cashier might be more reluctant to help you out by calling the supervisor. If you’re calling the store employees stupid, it won’t help your case.
On the other hand, a different, calmer approach might help you solve the situation faster. After all, you catch more flies with honey than vinegar, right? In other words, you can win someone more easily by gentle persuasion than by hostile confrontation.
