One reason that the task of inventing manners is so difficult is that etiquette is folk custom, and people have emotional ties to the forms of their youth. That is why there is such hostility between generations in times of rapid change; their manners being different, each feels affronted by the other, taking even the most surface choices for challenges.

Judith Martin (b. 1938) American author, journalist, etiquette expert [a.k.a. Miss Manners]

Common Courtesy, “On Etiquette as Language, Weapon, Custom, and Craft” (1985)
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