"If a teacher or anyone else in charge of other people can make them laugh, it gets them on-side. Incongruity is a useful device; the teacher or boss who can act unexpectedly and get laughs for it is on to a potential winner. But they must not cross the dividing line where they lose their dignity and the respect of others. It is tricky to know if the boss who can perform tumbles like a clown should demonstrate this to employees."
Graeme Garden qualified in medicine before working in television - best known in The Goodies
"Laughter induces physiological changes. If you feel truly happy, that is kind of the point to life, so laughter is definitely to be recommended. There are theories that laughter can help cure organic diseases as well as psychological illness, but it remains to be seen if this is regarded as a new form of alternative medicine."
Dr Bella Merlin, lecturer in drama at Birmingham University
"Humour must reflect what people can relate to. We've stopped believing in marriage as permanent, or even happy. Audiences don't buy it. Comic agony is the new trend for making people laugh. Thirty years ago, audiences were meant to laugh at the holiday camp scene in the Carry On film in which Barbara Windsor's bikini top flies off. I'm not speaking from a feminist viewpoint, but we've advanced beyond thinking that a woman being exposed is funny. In the play Cleo, Camping, Emmanuelle and Dick, there is a scene with Barbara Windsor rehearsing in the rain in her bathing costume and worrying about not exposing her nipples on camera. It's hilarious and agonising because it shows how awful the original situation was for her."