Being John Malkovich
The cult classic Being John Malkovich is rather trippy and completely original. It is thus easy to see how a random moment could have made it into the film. Remember when someone threw a can at Malkovich’s head and yelled, “Hey, Malkovich! Think fast!” Yeah, that was actually just an intoxicated extra who did it for kicks. Regardless, the director thought it was great and decided to put it into the final cut.
The Usual Suspects
Some directors are fine with adlibs, while others prefer strict adherence to the script. Director Brian Singer belonged to the latter. However, he gave the actors the opportunity to put their improvisation skills during the lineup scene in The Usual Suspects. Everyone was apparently laughing because Benicio Del Toro couldn’t stop farting! That’s why the scene was played for laughs, though it was originally meant to be serious.