"The Smiler With A Knife"

Humour is for them the all-consoling and (mark this) the all-excusing, grace of life. Hence it is invaluable as a means of destroying shame. If a man simply lets others pay for him, he is “mean”; if he boasts of it in a jocular manner and twits his fellows with having been scored off, he is no longer “mean” but a comical fellow. Mere cowardice is shameful; cowardice boasted of with humorous exaggerations and grotesque gestures can be passed off as funny. Cruelty is shameful – unless the cruel man can represent it as a practical joke. A thousand bawdy, or even blasphemous, jokes do not help towards a man’s damnation so much as his discovery that almost anything he wants to do can be done, not only without the disapproval but with the admiration of his fellows, if only it can get itself treated as a Joke. And this temptation can almost be hidden from your patient by that … seriousness about Humour. Any suggestion that there might be too much of it can be represented to him as “Puritanical” or as betraying a “lack of humour.”

But flippancy is the best of all. In the first place it is very economical. Only a clever human can make a real Joke about virtue, or indeed about anything else; any of them can be trained to talk as if virtue were funny. Among flippant people the Joke is always assumed to have been made.

C.S. Lewis, The Screwtape Letters.