The shoppers are out there scrambling around to get their shopping done in time to give out the gifts and lick their coupon paper cuts until next year, and they are full of stupid questions.
It's not their fault, they've been told since they were kids that "there are no dumb questions, just dumb answers", but that theory is easily disproven by a question that serves to redefine the meaning of stupidity.
There are stupid questions, and asking a stupid question does make a person look like a bit of a twit, but this man's question about how a bathroom works is, well, primordial? What's a better word?
See 20 People Share the Dumbest Questions They've Ever Gotten On The Job here (barely NSFW language)
C: How tall will this tree get?
Me: Well it is a maple tree so between 60 and 80 feet (reading the tag on the tree)
C: Ok but how tall with this tree get?
Me: You mean how tall will this particular tree get?
C: Yes because I want to compare it too one I saw at another place and I want to get one that will be the tallest.
Me: 73 feet. If it doesn't get that tall you can return it but you need to have the receipt.
C: Oh that is wonderful thanks.
I'm still baffled (and I can't pretend I was polite asking back in a very sarcastic tone: "Are you saying you honestly don't know how to use a stapler?').