Deliberate mistake: In Monsters, Inc., when Mike and Sulley walked through Monstropolis to go to the company, Mike said to Sulley "You've been jealous of my good looks since the fourth grade". In this film, we're told Mike and Sulley met in college. [In the commentary, director Dan Scanlon explained that there was a lengthy scene that would have followed Mike and Sully throughout their years in elementary school, but it would have slowed the pace of the film and would have reduced the impact of their rivalry. Rather than spend a lot of time on a back story, Scanlon decided to have Mike and Sully meet in college, even though this was inaccurate.]
Monsters University (2013)
1 deliberate mistake
Directed by: Dan Scanlon
Starring: John Goodman, Steve Buscemi, Billy Crystal, John Krasinski
Continuity mistake: In what is supposed to be a time-lapse scene, we see the Monsters University campus as nighttime ends and the sun rises. The shadows of the trees and buildings never change position as the sun gets higher in the sky.
Mike Wazowski: I've been waiting for this my whole life! I'm gonna be a scarer!
More trivia for Monsters University
Question: Why did the ROARs congratulate Sully and invite him to join them after seemingly losing the Scare Games to Oozma Kappa?
Answer: They said he could rejoin the fraternity as long as he proved he could be a great scarer, so his victory showed that he was good enough for them.