:P
Here's one I used once at an old job:
A lady came in to the convienance store I was a manager of complaining about the price of our gas (which by the way was the same or less than anywhere in town). Keep in mind this was at the end of a 14-hour day. I told her, "Don't blame me, blame the environmentalists." She replied, "Well, it's your store! YOU should make it cheaper!"
My reply: "Sorry, can't do it. By the way, you owe me a rib."
Just got a call with the dumbest question, asking us if we sell an advertiser's product. I said no, we sell our magazine.
I wanted to say, "That's about the stupidest question I've ever heard," but I think the caller realized her mistake because she got embarrass´d and told me,
"Why, honey, you just don't have the southern charm I was expecting."