I worked in a pizza restaurant when I was 16. They had a pizza they called a UFO pizza. It was just another slab of dough on top of a regular pizza, and it made it look like an orb, hence the name.

One day a guy that worked there was writing down a telephone order, turns around and says "hey guys, how do you spell UFO??" The owner looked mortified and just repeated "youuu eefff ohhh!!". He stared back in silence for a few moments before it hit him.