The Cherokee legend of "Two Wolves" tells of the me vs. me battle that is within us all. It is the battle to place the more recently evolved features of our brain in command of the primitive features in a way that gives us the best of both. In short, we are learning how to become the hero or hera (heroine), with self control, logical thinking, creative perspective taking and able to protect those we love if battle comes. We seek to become the "good wolf."
"Us vs. Them" is supposed to come after the "Me vs. Me" battle is resolved. After all, how can one successfully interact with others if one has not yet mastered the self? In this atomised socially darwinistic culture ever increasing proportions of the population fail to win "Me vs. Me" and are thus not psychologically mature. The advertising industry makes more profit from immature adults than mature ones. However, to become the best version of yourself, to have proper self control, to have both command of your empathy and logic, is vital to the formation of society and cohesive culture. When you have done this you will be ready to convert "Us vs. Them," into "Us and Them," and then onwards to a sense of "Us."