Hey , you , pick up that piece of garbage !   Huh ? Me ?   Yeah , you . I just saw you throw a piece of garbage on the ground . Can't you read the No Littering sign ? It's a $ 500 penalty for littering , so go pick it up and put it in the garbage can over there .   Why should I do that ? It's only a piece of garbage . Why should you care ?   Because this is a public place , and I want to spend my time here without having to look at your garbage . 