Some of us were brought up to think that classroom is a scared place for learning and have become used to serious atmosphere in which lessons are presented in a serious and formal way. It is normal for them to think so and to do so, but I would prefer lessons presented in an entertaining and enjoyable way. This preference of mine is a result of my own learning experiences and I ahve found out that it is psychologically explicable.
When a lesson is presented in an entertaining and enjoyable way, it does not mean that it is not serious and systematic. In fact, it is still serious because its purpose is still to import knowledge and to impart knowledge in a more effective way. And to achieve this purpose, it has to be presented in a systematic way. So the differnce between an entertaining lesson amd a serious and formal lesson is that the former has something additional, something that can make the learning process enjoyable.
According to my own experiences, an entertaining lesson is easier to remember than a dry and monotonous one. Psychologically, this is because knowledge imparted in an interesting way can leave on our minds a deep impression with more associations. Consequently, what is stored in our memory can last longer and is easier to recall. For instance, if a profound philosopgical truth is explained in detail and illustrated with an anecdote, both the truth and the anecdote will be stored in our memory. Afterwards, any information related to the philosophical problems or the anecdote can bring back this memory.
Furthermore, I have felt that an entertaining lesson can make me forget time and tiredness whereas a serious lesson can make me feel exhausted easily. Psychologically, these phenomena are explained in terms of span of mental concentration. During a serious lesson, we have to be serious and try hard to concentrate, but we can not do this for long before we are mentally tired. During an entertaining lesson, however, we get relaxed from time to time because of the well planned humour and the changing way of presentation. The result is that out span of concentration never runs out and that we can learn continuously and more effctively.
In short, I prefer entertaining and enjoyable lessons because I feel they are better because their advantages have psychological backing. But, I do not object to formal and serious lessons if some teachers are used to them. This is because it needs ability and skills to present a lesson in an entertaining way. If a teacher is not up to it, he may spoil the lesson.