What is one of your Favorite pieces of interesting trivia about a movie?

There are always just random interesting bits of trivia for various movies

More recently i had heard about in the movie Shrek when Donkey sees his swamp for the first time then makes fun of it then corrects himsef by saying i like that boulder that's a nice boulder

apparently that was a line put in there by the Animators cause they were really impressed with their work on the boulder