The path of the passive.

I have been repressing my anger for so long I no longer know whether or not I am justified in using it. My best friend is the Queen of all things passive and aggressive. I'm trying to find a way to:

A) Talk to her about it because I don't appreciate being anyone's whipping boy.
B) Use my anger in a useful and defensive way.
C) In general just stop being such a fucking door mat.

I don't really know how to be functional in relationships with people. I find it much easier bitching about people behind their backs rather than directly addressing issues. I am aware my methods make me totally dysfunctional but thats me...