It is rude to disturb someone who is studying.
Dave's brother Kyle is in his bedroom studying when Dave finds out a band he likes is coming to town.
Dave wants to tell someone about his excitement for the upcoming concert.
Dave calls up one of his friends on the phone and tells him all about his excitement for the show.
Dave runs into Kyle's room and tells him all about the concert and how he can't wait to go.
Kyle continues to study uninterrupted in his room and does very well in his classes.
Kyle is annoyed that Dave has broken his concentration and is wasting his time for something so trivial.