When you treat that person with respect but if that person didn't give u his/her respect, don't because of that person and assume everyone is the same and let your mind go wild by having thoughts in your mind like; "Why must I care so much when others don't even bother?", "It's so tiring to be the good person, no one really cares/bother anyway."
If just because other(s) don't give you the respect, doesn't mean other(s) don't deserve any respect. Don't because of the past experience(s) and ruin the "future" you. Don't simply because "I'm tired to be nice" and stop been nice.
And I always believe once you treat someone with respect as time goes by i'm sure you'll get the respect from that person or from others :-)
I always believe that no one born to be bad, is the people(s)/environment they are in that change their default self.
PS. Always treat others with equally respect without thinking to get the same in return.