Harry Potter and the Deathly Hallows, Part 2
The Harry Potter franchise's final movie had to be as perfect as possible. The make sure of this, Voldemort's Ralph Fiennes said his lines out of order and did different actions so that none of the other actors would get lazy with their lines. Everyone was on their toes when Ralph was on-screen, just like how they would be if confronted with the real Dark Lord, Voldemort.