Social distance aids in the preservation of good relations with people. Familiarity breeds, if not contempt, disrespect. In the famiglia, especially. Conventional usages, phony and formulaic as they often are, have their uses. They allow for civil interaction while preserving distance. "Good morning." "After you, sir." We all want respect even while aware of how little we deserve it and how insincere are those who show it.
A figure from Schopenhauer comes to mind. We are like porcupines on a cold night. They come together to stay warm but then prick one another and move apart. Trial and error leads to the optimal spatial adjustment.
The art of life, with its trials and errors, is learned by living, and learned best by living long.