[JeffL]

An accountant is someone who knows the cost of everything and the value of nothing.

An auditor is someone who arrives after the battle and bayonets
all the wounded.

A banker is a fellow who lends you his umbrella when the sun is
shining and wants it back the minute it begins to rain. (Mark
Twain)

An economist is an expert who will know tomorrow why the things
he predicted yesterday didn't happen today.

A statistician is someone who is good with numbers, but lacks
the personality to be an accountant.

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."