Sometimes people will piss you off on accident. Like while driving when someone pulls out in front of you and goes slowly for no reason. This makes you mad, but ultimatley you can get over it because you are sure they didn't mean to piss you off. If you mentioned it to them they might say they were sorry which also helps you move past the anger.
Then there are times when people do things that can only be reasoned to be delibratly designed to upset you. Like being consistanly rude to you or the ones you love without apology or explanation even after notification of the offense.
When this happens you have choices. You can either just assume that the person has poor manners or low self control and accept them for themselves. But really what is the benefit in that?
But if the condition continues, say for ten years or so off and on, I think it has become clear that the person just doesn't care for you. That they don't like you and or aggresivly tryin gto show you this. If this is your conclusion your only real option is cut things off. Life is too short and happiness too fleeting to waste time trying to make nice with someone who is not nice to you.
In my life I have had to discontinue realationships with friends and others because I no longer felt they were actually my friend or other. This is not usually an easy thing to do and is made all the more difficult with history, shared experience, friends in common, but when it needs to be done, it needs to be.
I am sad to think that I may have found myself in this situation where someone I thought was my friend is not and I don't think I can or should make any further effort to be involved with them. I am sad about this indeed.