Hi, dark dragon, welcome to PsychCentral (PC). I think you should always be as much like yourself as you can so other people can get a sense of you. If your girlfriend has trouble liking "you", then you probably don't want to be with that girl? Having to work at being "nice" and hiding the way you feel is no way to live and can't last.

I would have a talk with her and explain how you feel and that you're going to start trying to be more like yourself. Then the two of you can see how you're doing together. I think her comment on why YOU are with her, shows her fear for herself. Other people can't tell us how we feel, only we know how we feel and it's always "right" and always valid because it just is how we feel! So you should be more yourself and when she trys to tell you about YOU, gently remind her you're the expert on you. If she gets scared when you're angry (whether at her or someone else), that too is her fear, not yours! Anger is a natural, healthy, helpful emotion and if she has been raised to fear it, maybe you can help her learn it's okay. But she may have problems you can't help her with and that's okay too, just sad that she might not be the right girlfriend for you.