That people look at one another and are jealous of one another; that they exchange letters and have dinner together; that apart from all tangible interests they strike one another as pleasant or unpleasant; that gratitude for altruistic acts makes for inseparable union; that one asks another to point out a certain street; that people dress and adorn themselves for each other—these are a few casually chosen illustrations from the whole range of relations that play between one person and another. They may be momentary or permanent, conscious or unconscious, ephemeral or of grave consequence, but they incessantly tie men together. At each moment such threads are spun, dropped, taken up again, displaced by others, interwoven with others.

Georg Simmel, on individuality and social…, loc. 47