8) Monsters, Inc.
As Pixar have a perceived standard of quality to maintain, their movies often undergo a rigorous development process to ensure they’ve got things as perfect as can be. Monsters, Inc. is a prime example of a movie that went through several different versions until the final product was formed.
Here’s director Pete Docter on his much more adult original idea:
“My idea was that what it was about was about a 30 year old man who is like an accountant or something, he hates his job, and one day he gets a book with some drawings in it that he did when he was a kid from his mom, and he doesn’t think anything of it and he puts it on the shelf and that night, monsters show up. And nobody else can see them. He thinks he’s starting to go crazy, they follow him to his job, and on his dates, and all this— and it turns out these monsters are fears that he never dealt with as a kid.”
Another alternate version of the film would have focused on an inept monster befriending a human girl and her teaching him how to be scary. Said monster was George Sanderson, who later appeared in the final product as the furry creature who unfortunately keeps getting caught by the CDA.