It's wrong not to give advance notice of plans.
John is sitting at home when he realizes he hasn't seen his friend Tony for a while.
John wants to schedule a time to see Tony.
John calls Tony and asks when a good time would be then after they agree writes it down in his planner.
John decides that 10 minutes from now is a good time and goes straight over to Tony's house.
Tony is happy that John is planning an outing for the two of them and is excited to see him.
Tony is shocked to see John unannounced and is angry that John has interrupted his family time.