As I do from time to time, I visited Utah a while back and while there, my sister Ashley and I went to a movie. We decided to buy some popcorn. I approached the counter and told the man, "Hi, yes. I'd like a small popcorn, please." "Butter?" he asked. "No butter, thank you," was my reply. I then made some snarky remark about how the "small" must mean "small for a giant." I watched him fill the bag with popcorn and then proceed to the hot butter pumper machine. Just as he was about to pump, alarmed and flustered, I blurted out, "NO POPCORN!!!" Obviously I had meant no butter, but unfortunately I hadn't noticed my blunder. Congratulating myself for saving the day, I stared somewhat admonishingly at the man, confused as to why he stood there frozen in alarm, pausing for way too long before proceeding, which he did, at long last. He even said something like, "oh, no butter-- is that what you meant?" which didn't even register until I went on my snooty way and Ashley informed me of what I actually said.
Lessons learned: humility + I am crazy.