Psychology Vs. Law

A guy is looking for a place to sit in a crowded university library. He asked a girl:
"Do you mind if I sit beside you?"

The girl replied in a loud voice:
"I DON'T WANT TO SPEND THE NIGHT WITH YOU!"
All the students in the library started staring at the guy; he was truly embarrassed
and moved to another table.

After a couple of minutes, the girl walked quietly to the guy's table and said with
a laugh: "I study psychology, and I know what a man is thinking. I guess you
felt embarrassed, right?"

The guy then responded in a loud voice:
"$500 FOR ONE NIGHT? . . . THAT'S TOO MUCH!"
All the people in the library looked at the girl in shock.
The guy whispered to her:"I study law, and I know how to screw people."