When I get to know, how the father handles with his son, I was shocked but I think, you can also find reactions like this one's in the real life. Maybe not in a way, a coach hurts someone, but it's frequently difficult for a coach to get along with their ambition and will of reaching good results at sports. And sometimes, that's very difficult to realise because only the learner feels bad about how the coach handles with him.
A coach always want his pupil to be good and successful but sometimes this will can destroy the work of a pupil and his coach.