It's rude to insult people out of anger.
James was talking to his friend on the playground when Bill accidentally hit him with a basketball.
James wants Bill to be more careful with the ball.
"James tosses the ball back to Bill and says, ""Hey, be more careful""."
James calls Bill a clumsy four-eyes and tells him he's a loser.
"Bill says, ""I'm sorry I hit you - I'll be more careful""."
Bill chases the ball down and throws it at James deliberately.