An actuary is someone who brings a fake bomb on a plane because that decreases the chances that there will be another bomb on the plane. (Laurence J. Peter)

A programmer is someone who solves a problem you didn't know you had in a way you don't understand.

A mathematician is a blind man in a dark room looking for a black cat which isn't there. (Charles R. Darwin)

A topologist is a man who doesn't know the difference between a coffee cup and a doughnut.

A lawyer is a person who writes a 10,000-word document and calls it a "brief." (Franz Kafka)

A psychologist is a man who watches everyone else when a beautiful girl enters the room.

A professor is one who talks in someone else's sleep.

A schoolteacher is a disillusioned woman who used to think she liked children.

A consultant is someone who takes the watch off your wrist and tells you the time.