Kinyan 18 Mi'ut S'chok - Rav Sholom Schwadron Knew How To Make Them Laugh
Rav Sholom Schwadron was once asked how can he tell so many jokes if the Mishna says that the way to be Koneh Torah is by minimizing "S'chok"? He answered with a Mashal. If a smart child refuses to take his bitter medicine then you scare him with the dire consequences. But if the child is to immature to understand then you tell him a joke. When he opens up his mouth in laughter you quickly drop the medicine inside. "Our generation", said Rav Sholom, "absolutely refuses to accept mussar". So I get them laughing and when they don't notice I quickly drop in the mussar before they have a chance to close their mouths."
Like all the other things the Mishna advises to minimize, S'chok is not blacklisted, rather it needs to be used in small and careful measures. "Eis Livkos V'Eis Lischok", there is a time and place for everything (Koheles 3:4). The great Amora, Rabba, would say a joke before beginning his shiur. True that joking is extremely dangerous and leads to all kinds of disatrous things as Chazal tell us, however it is a very powerful tool dispensed by a wise practitioner. Unfortunately it is too dangerous for most of us to try on our own, too often, without getting burned by its fire. The Torah tells us that upon hearing the besura that they will have a son both Avrohom and Sara each expressed Tzchok. Yet Sara was taken to task for it and not Avrohom, because only Sara's crossed the very thin line.
The gemara (Brachos 31b) tells us that in Olam HaZeh we may not joke too much, but in Olam Habah, "Az Yimalei S'chok Pinu", we will be full of S'chok. In the light of truth, S'chok will be the greatest expression of our pure inner-self. Until then we need to reign in the jokes if we want to acquire our full portion of Torah.