It's all in how you say it

I was at FedEx yesterday, expressing a tennis ball to my mother. (No, really.) (Don't ask.) A young man named Sean was helping me. His supervisor appeared and explained to a co-worker, "I'm here to give Sean a break." (i.e., so he could take a 10-minute break, or whatever.) As a joke, Sean responded, using the expression in the tone he would use as if annoyed or angered by something outrageous someone else might have said or done, saying, "Gimme a break!" We all laughed -- the words were right, but the tone was off.