If you don't like 'Mean Girls', you can't sit with us!
You can't buy a dress without your friends' approval, and in girl world dating a friend's ex-boyfriend is so not fetch.
Today, October 3rd (aka the very day Cady asked Aaron Samuels what day it was, and she replied, "It's October 3rd."), is the unofficial National Mean Girls Day. So there's really no better time than now to embrace your inner mean girl and use these 19 signs as a guide to your obsession.