Allowing an unimportant mistake to pass without a comment is a wonderful social grace […] Children who have the habit of constantly correcting should be stopped before they grow up to drive spouses and everyone else crazy by interrupting stories to say, “No, dear — it was Tuesday, not Wednesday.”

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

(Attributed)

Widely attributed to Martin, but I am unable to find an original source.