“If you really experience all of that for another (concern and care for, and the value of, another person) then it follows that you act in accordance… just look at the reality of how people treat each other. Is it well-natured? Generous? When there’s love, you know it. You don’t scrounge up a case for it.“

Well put.  Often we find ourselves scrounging up a case, trying hard to believe in a mutuality that may have once been there but is no more.  I always think of friendship/intimacy as, above all, a desire not to hurt the other person.  First, do no harm, seems very basic, if you care about the person. 

Some people can’t help the harmful behavior, they can’t even see they’re behaving that way, can’t understand why it hurts the other person, they may get defensive and angry when you bring up that you are hurt. 

This all makes it impossible for them to take responsibility for their hurtful actions and change their reflexive behavior in any helpful way.  Conflict freaks them out, they can’t fix what’s chafing, what’s looming, what has become intolerable, and once you see this, hope for anything better disappears and it’s time to walk away.  Very fucking sad.