Mean Girls (2004)
You'd be hard pushed to find anyone who was a teenager in the noughties and can't quote at least one line from Tina Fey's whip-smart deconstruction of high school dynamics at their bitchiest and most cliquey. Starring a fresh-faced Lindsay Lohan as wide-eyed new student Cady, this is an endlessly enjoyable, quotable and sharp-witted teen comedy.