There is no government circular stating that classrooms must be devoid of laughter and, in fact, some teachers work laughter breaks into their lesson plans. The key here is balance. Use too much humour and you risk appearing to need adulation and affection from your pupils. Aim to throw in occasional high points of humour but it is possible to get carried away and become so delighted with your own wittiness that you fail to notice that the lesson is deteriorating as a result, so:
be sure not to waste time be aware that any jokes or funny tales you tell will be repeated outside the
lesson, so keep them tasteful and inoffensive never employ humour at the expense of pupils, however well you know
them. (Holmes 2000, p. 51)
Thoughtful children would probably describe the desirable qualities in teachers in these terms:
To be a good teacher you need to be very patient, clever, well organized, quite humorous, able to maintain order, set a good example to everybody and fair at all times.