Well, I have had my fair share of this type of people. I have
always tried treating everyone nicely and I found out you cannot
really expect people to treat you back the same way. In another
word, be nice but don't expect your kindness to be returned. If
this bothers you and you feel being nice is not worth it, then you
can try being bad 
For me, I feel it is easier to be nice to people, I guess it is
part of my subconscious. So do it not for the sake of having them
return your kindness, but do it for yourself. Being nice gives you
a good feeling right? 
I do it for my own self satisfaction.
But then of course there are exception. I can be evil when I want
to :twised: