Lal said:
“People do not understand how serious the suffering in the rebirth process is.”
My personal experience, especially since coming to this site, is that a more serious attitude is more beneficial in learning Dhamma.
Lal keeps emphasizing the danger of the rebirth process, and hence the urgency to get out of the 31 realms, starting with the apayā. When we learn Dhamma in this context, the concepts stick to the mind better.
A friend of mine told me just last week something like: “I listened to a talk of Thero X; I now forget what he was talking about, but I still remember his jokes.”
A number of theros do utilize jokes and humor in their talks. I suppose the intention is to keep the audience entertained (and thus attentive). The drawback of this approach is that it is very easy to lose sight of the future suffering, which is the crux of the matter.