You shouldn't judge someone's body weight.
Sally is starting a new school today.
Sally wants to meet new people.
Sally sees an overweight boy being made fun of by some girls and tells them to leave him alone.
Sally sees some girls making fun of an overweight boy and joins in and laughs with the others.
The boy appreciates Sally standing up for him and the two become good friends.
The boy has his feelings hurt and Sally feels guilty afterwards.