This one is actually about my father. As a boy, he thought that it was tradition to order the weirdest food whenever you went to a restaurant (there weren't many restaurants around where he lived back then and most of the few ones were fancy).
One time, he ordered lambs' brains and ox tongue, which he disliked. Another time, in a different restaurant, he ordered moose that still had the bullets in it (!), and in a third restaurant, he ordered venison, but when it was served, he was very disappointed and said, "But where are the antlers?!".
A childhood belief about nasty food

others believed things like this
- When you ordered small fries they were just shorterAnon
- that the chinese dish Hunan beef was really made from humans. To this day, I have never ordered it. — kristen
- I used to believe that "BYO" was a name of a restaurant.— Ames
- I thought the tip jar at the restaurant was so people could give the chef cooking tips for how to cook better.Anon
- My parents used to own a Restaurant. I belived the lobsters in the tank were pets.— Ned
- I didn't mind eating lambs brains when I was a kid because I thought it would make me smart.Anon