Being John Malkovich
A lot of things are certainly weird in the film Being John Malkovich. Apparently, the screenplay allowed actors to improvise. Case in point: the scene where somebody throws a can directly at the main character and shouts, “Hey Malkovich! Think fast!” The extra was allegedly drunk and was responsible for that scene!
The Usual Suspects
There is a scene in The Usual Suspects that is totally different from how it should be and was actually improvised. During the filming of the scene, Benicio Del Toro kept farting, and they couldn’t stop themselves from laughing. During the break, the director, Brian Singer, reproached the actors, but they ended up laughing more because of that. Singer chose to accept the tone, and we bet that was the best thing he could do.