Movie 1: Indiana Jones 'Sword VS Guns'

       This scene was originally was supposed to be a full-on sword fight but Harrison Ford (who played Indiana Jones) felt ill and didn't want to put in the energy of this scene so he pulled out a prop gun to shoot at the actor. 

Movie 2: The Shining "Here's Johnny!"

        During the filming process the director (Stanley Kubrick) always cause his actors into a mental spiral mainly towards Shelly Duvall and Jack Nicholson help Stanley with that. This scene Jack borrows a popular late-night catchphrase to add comedy and creepiness towards this scene. This scene became so horrified Duvall's screams started to become real. 

Movie 3: Pirates of the Caribbean "I got a jar of dirt!"

        In the script Johnny Depp was supposed hold up the jar a taunt the character Davy Jones but Jonny Depp didn't like that so he instead sings a little ditty to taunt Davy Jones. The actor's reactions were real and made this scene funnier than it was supposed to be especially when Johnny Depp accidentally fell down.