Spoiling movies for people could make them angry at you.
Mark invites his friend over to watch his favorite movie.
Mark wants to share the movie with his friend.
Mark enjoys watching his friend's reactions to the plot twists in the movie.
Mark announces the ending halfway through the movie in his excitement.
Mark's friend loves the movie, and they now have something else in common.
Mark's friend leaves after saying there is no point watching a spoiled movie.