It is bad to do things to hurt others.
Ron is upset because he doesn't think his family is paying enough attention to him.
Ron wants his family to know how he feels.
Ron explains to his parents that he feels left out, and asks if they can do something together.
Ron hits his sister to get his parents' attention, then throws a tantrum and calls them all stupid.
Ron's family realizes he wants attention, and they do activities together.
Ron's sister cries in pain, and his family is put through unnecessary drama, and Ron is grounded.