I hate this girl but my BEST FRIENd IS FRIENDS wit her!!?

my friend named kennidy gets mad easily. it gets annoying. when we r mean 2 her she always wants pay back and ahe is always telling me 2 SHUT UP about my jokes. i neva say thta bout her jokes. she also rolles her eyes @ every thing i say. my best friends is friends wit her. so i have 2 hang wit her a lot. i cant tell my best friend i dont lik her though cauz she is one of her friends and ir would be werid.. Kennidy can be nice som times though...Kennidy likes me as a friend 2!