I do not deny that Kim had a horrible, horrible childhood. As have many of us. Having said that I beleive that Kim's frame of reality is that if you don't kiss her a$$ then you are her enemy. And she keeps very close score of every slight that she 'perceives' someone has gave her.
Jill and her didn't click. And that is real life. Not everyone is going to be either Jill or Kim's friend.
Kim evened the score by mouthing off when Jill found out she was graduating. She has been waiting for her chance to be reigning senior member. Guess it hasn't worked out that way for her.
I see a lot of improvement in Kim, but she has a long, long way to go before she becomes the loving person she wants to be.