Emma's Slap

Originally the script called for Hermione to slap Malfoy as opposed to punching him in 'Prisoner of Azkaban'. During rehearsal for the scene Tom Felton told Emma Watson to slap him, however he had intended for her to not actually hit him, and thus was taken by surprise when Emma smacked him across the face as hard as she could. Emma said she felt terrible about it afterwards and didn't know what she was thinking.