Etiquette

Moving parts in rubbing contact require lubrication to avoid excessive wear. Honorifics and formal politeness provide lubrication where people rub together. Often the very young, the untraveled, the naïve, the unsophisticated deplore these formalities as “empty,” “meaningless,” or “dishonest,” and scorn to use them. No matter how “pure” their motives, they thereby throw sand into machinery that does not work too well at best.

Time Enough for Love, by Robert Heinlein