Mare was actually one of the few characters...

with some depth. She was a follower who was clearly insecure and desperately wanted to be popular like her poorly chosen idol, Ally. I did feel some sympathy for her.
Even Phoebe had some to flesh to her as well. We find out she's the troubled tomboy of the girl's cabin. Perhaps even promiscuous but unlike Ally, I don't think she was a bully but she seemed like the type who got into fights at school. According to Demi, she was rebellious at home and her parents were at their wit's end so they send her off to camp.
Every other character is just there:
Demi is smart.
The Schoets are stoners.
Lea's a tattle.
Ally's a promiscuous bully.
And all the guys are just dumb.

She melts in your mouth, she melts in your hands.