The narcissism of minor differences

It is clearly not easy for men to give up the satisfaction of this inclination to aggression. They do not feel comfortable without it. The advantage which a comparatively small cultural group offers of allowing this instinct an outlet in the form of hostility against intruders is not to be despised. It is always possible to bind together a considerable number of people in love, so long as there are other people left over to receive the manifestations of their aggressiveness. I once discussed the phenomenon that it is precisely communities with adjoining territories, and related to each other in other ways as well, who are engaged in constant feuds and in ridiculing each other - like the Spaniards and Portuguese, for instance, the North Germans and South Germans, the English and Scotch, and so on. I gave this phenomenon the name of 'the narcissism of minor differences', a name which does not do much to explain it. We can now see that it is a convenient and relatively harmless satisfaction of the inclination to aggression, by means of which cohesion between the members of the community is made easier.

(Sigmund Freud: Civilization and its discontents)

The cantons of Shant were alike only in their mutual distrust. Each regarded as Universal Principle its own customs, costumes, jargon and mannerisms, and considered all else eccentricity.

(Jack Vance: The Anome)

Except for rivers, the land lacks natural boundaries, but boundaries and borders aplenty have been created, to delineate 1,562 separate dominions, each jealous of its identity, each cherishing its own rotes and rites, each celebrating its distinctive cuisine and scorning all others as filth and scum, each considering itself the single home of civilization among 1,562 barbaric, incomprehensible and unpleasant neighbors.

(Jack Vance: The Book of Dreams)