It is rude to yell at others.
Alex's friend took advantage of him very badly when asking him to help him move.
Alex wants to tell his friend how wrong it was.
Alex talks calmly and rationally to his friend about what happened.
Alex screams at his friend the next time he sees him over what he did.
Alex's friend understands now, and apologizes and promises to never do it again.
Alex's friend can't believe he's this upset and thinks he's being hysterical, dismissing him.