Catty

Ugh, why are females so mean to each other? Why do they take out their insecurities on other women? What's the point? I'd like to think that feminism, post-feminism, and general intelligence would have begun eliminating catty behavior by this point.
I am 24 years old and I still feel like I'm in high school whenever I have to interact with women on a social level. It's pathetic. I am not threatening. My prescence should not threaten their's. It is so so so old. I am not against women occasionally disliking me, but I wish they would let me give them a legitimate reason first.