Whether you're feeling nostalgic for the classic film Mean Girls because you just saw the reboot in movie theaters (and didn't know it was a musical (People)) or because Y2K trends are all over your FYP page, there's no denying that people still have a lot of love for this Tina Fey-penned film which came out 20 years ago. It's the movie that spawned a million catchphrases, some of which many fans are still using today.