She was alert, suspecting this man, and responds by yelling, "No, I won't sleep with you tonight!"
Customers in the bar started staring at them. The embarrassed guy quickly returns to his table dejected and ashamed.
The young woman waits a little and then goes to the guy to apologize. With a smile on her face she says, "I am sorry if I embarrassed you. You see, I am a college student in psychiatry and I am putting together a thesis as to how people react to embarrassing moments."
The cunning guy now yells loudly, "What do you mean $500?"