You shoud apologize when you interrupt someone.
Lisa has just received some news her friends might find mildly important, and she sees her friend across the park in the middle of a game.
Lisa wants to tell her friends the news.
Lisa calls out to her friends apologizing for distracting from the game but says they'll want to hear the news she has.
Lisa runs over into the middle of her friend's game forcing them to stop and tells them the news.
Lisa's friends are enthralled by the notion and eagerly await the news.
The friends are annoyed that Lisa interrupted the game they were playing to tell them the news.