Never say a humorous thing to a man who does not possess humour. He will always use it in evidence against you.
Source: Quoted in: Hesketh Pearson, Beerbohm-Tree, ch. 12 (1956).
-- Herbert Beerbohm Tree, (Dec 17 1853-1917), English actor, theater manager; He was one of the great figures of the English theatre, who became the most successful actor-manager of his time.