Why Do We Seek Labels?

How is it that a generation raised on “Be Yourself” entertainment is so obsessed with conforming to labels? How can we, on one hand, talk so much about how our race, gender and sexuality doesn’t define our potential and value, and then turn around and say without a trace of irony, “Oh, I’m a Cancer, that’s why I’m so emotional”? Why are we so in need of being sorted?