Have you noticed how often people are happy to hear the same joke, over and over again? One reason, of course, is that they have not probably forgotten the details of the joke, but I am sure it also has something to do with getting the same 1 more than once. So when a person who has just started telling a joke asks his audience, 'Do you know it?' or 'Have you heard it before?' people always answer something like, 'It doesn't matter, let's hear it again.” It is not 2that if a joke is worth hearing, it is worth hearing several times. I think it was Ogden Nash who once said that it is probably better to have an infectious disease than to have a sense of 3. He argued, tongue-in-check no doubt, that although people who possess a sense of humour have a good time, they never 4achieve anything important, whether good or bad. This, thought Nash, is because when people with a sense of humour begin to do anything 5, they can't help noticing how funny they look doing it, so they stop to have a good laugh at themselves. As a result, what might have been a great achievement is left unfinished.