You shouldn't be cruel to people.
Rob walks into the kitchen and sees his sister Susie approaching the counter to get a cookie.
Rob wants a cookie to eat for himself.
Sam allows his sister to get a cookie and then grabs another for himself and eats it.
Rob knocks the cookie out of Susie's hand and eats it.
Susie feels happy and enjoys eating the cookie.
Susie feels sad and upset and begins to cry.