I work in an office, and we used to have a postal delivery guy who was generally friendly and talkative. Sometimes his jokes weren't all that funny, he could border on being a jerk, but it was never too bad.
Well, one fall day, he came in, and I asked him if it was cold. Apparently, this was the wrong place and time to do so. He stared at me for a second, and then said in a loud and annoyed voice:
"Of COURSE it's cold! Why wouldn't it be cold?"
I just sat there like this as he left: ...
Now, in fairness to him, my question was probably ill-placed, which is why I consider this closer to a WTF. I was sitting in a warm office while he was out in the cold. But I wasn't trying to be the type of customer who tells waitresses "oh it must suck that you're working on Easter!" and smiles smugly. I just asked a silly question because I epically fail at small talk. Chillax.