What is the central ideas

Mean Girls depicts high school as a pressure cooker environment where every student feels compelled to abide by stringent social norms. Both Damian and The Plastics discourage Cady from joining the Mathletes and pursing her mathematical ability, calling it "social suicide." The bylaws of The Plastics in general render all individual decisions subject to the approval to the rest of the group, which makes true individuality impossible. Ironically, Cady's attempts to become more conventionally appealing drive her love interest away, who is more attracted to her quirks. The characters Damian and Janis, especially in their purple tuxedos at the film's end, represent the spirit of the individual over the norms of the crowd.