Ben Orlin in Math With Bad Drawings:
Economist: No! That’s so inefficient. Let’s each write down the amount we’re willing to put in, then auction off the remainder at some point on the contract curve.
Physicist: Huh?
Mathematician: Like most economics, that’s just gibberish with the word “auction” in it.
Engineer: Look, it’s simple. Total your items, add 8% tax, and 18% tip.
Mathematician: Sure. Does anybody know 12 plus 7?
Computer Scientist: You don’t?
Mathematician: What do I look like, a human calculator? Numbers are for children, half-wits, and bored cats.
More here. [Thanks to Alon Levy.]