I had a cop yell at me once because I wouldn't accept a return that had obvious physical damage.
I stated with a poker face, "You are angry, but that does not change the fact you closed your laptop on a pen, cracking your screen... aaaaand our warranty does not cover physical damage. I could lose my job returning this."
I continued as he was trying to figure out what to say, "Tell me something... what are some of the things you could lose your job over? Can you imagine ever deciding to do any of those things, just because some petty criminal YELLED at you?"
He quietly shuffled off.
Got high fives from everyone, including the floor manager, after he was out of sight.