"What's the usual tip?" a man growled when Little Johnny delivered his pizza.
"Well," Little Johnny replied, "this is my first delivery, but the other guys said that if I got a quarter out of you, I'd be doing great." "That so?" grunted the man. "In that case, here's five dollars." "Thanks," Little Johnny said, "I'll put it in my college fund."
"By the way, what are you studying?" asked the man.
"Applied psychology," replied Little Johnny.