The prep of this breakfast club in disguise, Mimi is easy to dislike, as are most of the characters in the show. It isn't that she can't take care of herself, or that she isn't smart, she just likes to whine and is way to concerned about her appearance. She is the stereotypical prep.
She plays only a token role in the plot, like most characters, and is only there to represent here particular clique in the show.
The Cronie of the Prep. Palmon is there to agree with what Mimi says and get up in anyone's face who happens to disagree. And She is a plant. Anything else I missed? Not much there when it comes to brains or personality.