“A joke is a very serious thing.”
“I Take Life Very Seriously: One Joke At A Time.”
“There are things that are so serious that you can only joke about them.”
“A true Englishman doesn't joke when he is talking about so serious a thing as a wager.”
“and a charge of lying against someone whom you have always found truthful is a very serious thing; a very serious thing indeed.”
“But very quickly they all became grave again: for, as you know, there is a kind of happiness and wonder that makes you serious. It is too good to waste on jokes.”