It is wrong to punch children.
Bobby's son John knocks over their big screen TV and breaks it.
Bobby wants to punish his kid and teach a lesson.
Bobby holds his anger in and sends his son to his room telling him to be more careful around electronics.
Bobby allows his anger to take hold of him, and he punches his son in the arm as punishment.
John makes sure to be careful around the house and his relationship remains strong with Bobby.
John stops liking his dad Bobby and their relationship deteriorates to nothing.