Well, frankly I believe it is a biological trait, an unavoidable natural instinct manipulated by propaganda. Humans and their ancestors survived for several th

Well, frankly I believe it is a biological trait, an unavoidable natural instinct manipulated by propaganda. Humans and their ancestors survived for several thousands of years in bands and tribes with between 10 and 50 individuals. Social cohesion and collaboration among them was essential for survival in confrontation with other animals or tribes fighting for the same resources (or females). It is unavoidable that evolution shaped them to develop a desperate wish to "belong" to a group. Some call it tribalism. Nations just grab this tribalism and turn it into ideological justification for everything as in: "my country, right or wrong". Religions, political affiliations, corporations and sport associations use that trick too.