I was working retail at a huge department store chain one holiday season. One day right before Christmas, we had huge rush of people last minute shopping and the lines were incredibly long. I had been at my register for hours without a break because the line never would die down.
Anyway, this lady and her young daughter were next. I was ringing them up and they were nicer than most, actually.
She even said something like, "You must be so tired. This place is a madhouse!"
I laughed and said "Yeah, but it's Christmas; what are you gonna do?"
That's when she looked down at her daughter and said, loudly, "Honey, THIS is why you go to college."
My first instinct was to leap across the counter and throttle her. After a beat to take a breath, I just looked at the brat dead in the eye and deadpanned, "I did go to college. It guarantees nothing. Have a great Christmas."
The lady sputtered and gasped and I shouted "NEXT!" and the mean old lady behind her elbowed her out of the way. That mean old lady made my week.