Why do some girls compete with each other so much?

I guess today and this past week I’m just reminded..

Sadly I just wanna be a girl’s girl and friends with almost everyone, but once I finally realized.. oh they don’t wanna be my friend or a frenemy bc they’re competing or don’t like me for whatever reasons despite I’ve been trying to be friendly. I no longer respect nor see them the same way. I just don’t like it and not really with girls competing, trying to one up another girl, being mean girls, and such
Why do some girls compete with each other so much?
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