I'm doing research now that has wandered over to A.V. Hill, Keynes's brother-in-law. This is a wise line from his autobiography, which is a reference to his years in Parliament (in a seat that was initially offered to Keynes himself, actually):
"After many years I came to the conclusion that it never (repeat never!) pays to lose one's temper; but that occasionally in a good cause it is useful to pretend to lose it."