Why are some women such bitches to each other?

Every once in a while I run into a woman who has the most rotten attitude towards me. I’m super chill and it really stumps me when it happens, especially when I didn’t do anything to antagonize her.
Why are some women such bitches to each other?
Updates
+1 y
I had this chick in high school tell me that she didn’t like me. I had never talked to her before and she was always so mean to me. I never did anything to hurt her and even tried to figure out what her problem was but never figured it out.
Why are some women such bitches to each other?
Post Opinion