Aliens landing in Britain would be bemused to find that we have a day officially devoted to jokes, April Fool's Day. The British are addicted to jokes, seeing them as an effective emotional release; post-disaster jokes are tasteless, tactless, cynical, exploitative and often horribly funny.
But the beauty of a joke is often lost on the beholder. Jokes can wither and die in the face of incomprehension or be artificially applauded in the name of 'politeness': a rich man's joke is always funny. Worse still, a joke can alienate or even cause offence, both in joke-teller ("they just don't get my sense of humour in this country") or in the audience, ("actually, my wife is blonde and that's just rude").
As in all things, moderation is the key. Telling a joke can be a real conversation-stopper - if you're itching to relay the rib-tickler you heard earlier, appreciate that it will be disruptive, and tell it as quickly as possible before returning to real conversation.
The second rule is to match your material to your audience: a filthy gag that had you and your friends weeping with laughter is probably not one to tell on your first day in the office. Great-Aunt Myrtle does not want to hear the latest blonde joke; that first date may not appreciate an erectile dysfunction side-splitter. Now, have you heard the one about the Englishman, the Irishman and the Scotsman?...