Heathers (1989)

At Westburg High, you're either a Heather or a nobody. And while Veronica Sawyer (Winona Ryder) may not be named Heather, she's a Heather in spirit, waging battles in the full-scale popularity war. But just when it all gets to be too much, she meets mysterious newcomer Jason (Christian Slater), who offers her the perfect -- albeit deadly -- solution to end the Heathers' social tyranny. Teen angst has rarely been this darkly funny or poignant.