My Dear Son:
In the perfect world—one, say, where all people observed The Golden Rule, there would exist no cliques. As defined in social studies, clique originated from a French word meaning a group of two or more people who interact with each other regularly and intensely. In school settings, cliques usually revolve around clubs, gangs, academics, fads, or social trends. Cliques can even develop in family settings, as well.
All too often the operative word in maintaining a clique becomes “us against them.” Cliquish behavior assumes that the other guy cannot or will not fit in as part of the group because―well, you name it. Cliques have been formed for virtually every reason under the sun.
In order for a clique to continue to function, the participants must believe that there is more that separates them from the outsiders than what they might hold in common. So cliques are formed first by judging others as different, and they continue to survive on that basis. The problem is, we must first be able to define and identify something before we are able to identify anything as different.
This is the log in our own eye, our ability to see, name, or even quantify a difference in others in the first place. I think you will see that, if you couldn't identify with some of the differences of outsiders, they would not remain outsiders. They would not show up on your radar at all, or even enter into you personal awareness. So, you could say, in order to continue a clique, you must first exclude the very people you understand so well.