Literal Humor

I read this joke the other day and got a laugh from it:

A wife asked her husband to go to the market.  "Buy one carton of milk, and if they have avocados, get six."  A short time later the husband returned with half a dozen cartons of milk.  "Why did you buy six?" asked the wife.  Replied the husband "they had avocados."

After writing logic code for the past week, I found this especially funny.