I just love this one… Got it from a student at my former school.
Don’t ask a computer programmer to go shopping
A wife asks her husband, a computer programmer; “Could you please go to the store for me and buy one carton of milk, and if they have eggs, get 6!”
A short time later the husband comes back with 6 cartons of milk.
The wife asks him, “Why the hell did you buy 6 cartons of milk?”
He replied, “They had eggs.”