What is something you 'learned' from a movie only to discover its not actually true?

People often say that they've learnt something from seeing it in a movie. But can you think of anything you thought you'd learned from a movie only to then discover it was never actually true? One example might be how gun silencers are portrayed in movies not being at all accurate. Or, a personal example was I learned the tale of A Christmas Carol from the Muppet's adaptation and only recently discovered that there was only 1 Marley character in the original story.