My need for social relationships (if by that we mean relationships other than romantic relationships), which started very weak, had declined to nothing over the years. Was that normal? It’s true that humanity’s unpalatable ancestors lived in tribes of a few dozen individuals, about the size of a hamlet, and that that formula pertained for a long time–both among hunter-gatherers and among the first farming populations. But time had moved on since then; there had been the invention of the city and its natural corollary–loneliness.

Serotonin: A Novel
Michel Houellebecq