You shouldn't spoil movies.
Sean just saw a great film and is exited to tell his brother Mike he needs to see it.
Sean wants to recommend the film.
Sean calls up Mike and tells him how good this movie was while being careful not to reveal too much about the plot.
Sean calls up Mike and in his excitement reveals the ending to him.
Mike is intrigued and buys himself some tickets to see the film.
Mike doesn't want to watch this film because he knows what will happen already.