payback

A very shy guy goes into a bar and sees a beautiful woman sitting at the bar. After an hour of gathering up his courage he finally goes over to her and asks, tentatively, "Um, would you mind if I chatted with you for a while?"
She responds by yelling, at the top of her lungs, "No, I won't sleep with you tonight!" Everyone in the bar is now staring at them. Naturally, the guy is hopelessly and completely embarrassed and he slinks back to his table.
After a few minutes, the woman walks over to him and apologizes. She smiles at him and says, "I'm sorry if I embarrassed you. You see, I'm a graduate student in psychology and I'm studying how people respond to embarrassing situations."
To which he responds, at the top of his lungs, "What do you mean $300?"