Know your subject matter

[carwash66]

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."