Freud observed that people who have much in common can still fight bitterly because they grow overly sensitive to the disagreements remaining between them. He called this the “narcissism of small differences”: “It is precisely the minor differences in people who are otherwise alike that form the basis of feelings of hostility between them.”

In Gulliver’s Travels, 11,000 people die in a war between the Big-endians, who break their eggs at the big end, and the Little-endians, who break them at the little end. A Lilliputian admiral attacks Gulliver because “he had good reasons to think you were a Big-endian in your heart; and, as treason begins in the heart, before it appears in overt acts, so he accused you as a traitor on that account, and therefore insisted you should be put to death.”

For a 1752 essay, Samuel Johnson compiled these notes on how a man’s outlook changes as he grows older:

Hope predom. in youth. Mind not willingly indulges unpleasing thoughts. The world lies all enameld before him, as a distant prospect sun-gilt — inequalities only found by coming to it. Love is to be all joy — children excellent — Fame to be constant — caresses of the great — applauses of the learned — smiles of Beauty.

Fear of disgrace — Bashfulness — Finds things of less importance. Miscarriages forgot like excellencies; — if remembered, of no import. Danger of sinking into negligence of reputation. Lest the fear of disgrace destroy activity.

Confidence in himself. Long tract of life before him. — No thought of sickness. — Embarrasment of affairs. — Distraction of family. — Publick calamities. — No sense of the prevalence of bad habits. — Negligent of time — ready to undertake — careless to pursue — all changed by time.

Confident of others — unsuspecting as unexperienced — imagining himself secure against neglect, never imagines they will venture to treat him ill. Ready to trust; expecting to be trusted. Convinced by time of the selfishness, the meanness, the cowardice, the treachery of men.

“Such is the condition of life, that something is always wanting to happiness,” Johnson wrote in the finished essay. “In youth, we have warm hopes, which are soon blasted by rashness and negligence, and great designs, which are defeated by inexperience. In age, we have knowledge and prudence without spirit to exert, or motives to prompt them; we are able to plan schemes and regulate measures, but have not time remaining to bring them to completion.”