I can see why you feel dissapointed and angry. I can guarantee that although you can list 10 things you have done for her she doesn't see it that way. She has a list that she sees as equivalent. However, it is ok you to say, "Hey W, I am really disappointed that you didn't want to go to so and so's party. It is something important to me that I wanted us to go to together." - something like that. Be honest. Call her on it then you can let go of it.
