It is actually an "old" quotes.
Because .. if you act like "whatever", then someone did the same to you, what will you feel? Will you just be OK with that? always put yourself, in others' shoe."Treat others like you wish to be treated"
I always try to remember this quote,and apply it in my daily life. or else. Just make sure that all my words and behaviour isn't hurtful, cos i know imma "truth-hurts" person.