Human are very social creatures
We can't live alone. A very important part of us is the social identity. We do have our self-identity and another social identity; that's why we can die for the bigger thing we belong to even if the thing we sacrifice ourselves for will not hurt us in person
Another identity that we can't live without is (THE OTHER) identity. Every one of us has a self (other) and as part of a larger groups we have many (others) that oppose the and contrast the self/the clan, make it more visible and distinct and prove its existence and superiority
Countries/religions/races/colors/languages/sports teams ….etc. are prove of what I am trying to make clear; that the presence of us in a larger (identity) and the presence of the (other) identity is essential for us
Even if we are among people who are very much the same like us, we will find a way to make differences and split up to form a kind of bonding with a specific group and create the (other) one, the enemy. And that happens very natural and very automatic
Even in businesses, we make fans and teams and get at each other: Microsoft vs. apple – iPhone vs. android – windows vs. mac … etc.
And we are very influenced by people in our/ not in our groups, or to be a more accurate I mean people we consider to be/not to be in the groups we belong to