According to
this article, what we know as Jewish humour today (as well as the numerous examples of comedy, from Hollywood gross-out to the African-American tradition of "the Dozens", influenced to some degree by Jewish comedic culture) owes its existence to a rabbinical edict, passed in the wake of a wave of pogroms, banning most forms of jollity, and driving almost all forms of humour in the Yiddish-speaking world into extinction. Only one type of entertainer, a kind of crude, cruel jester named the
badkhn, was spared prohibition, on the grounds that his shtick wasn't actually funny:
The badkhn was a staple in East European Jewish life for three centuries, mocking brides and grooms at their weddings. He also was in charge of Purim spiels in shtetl society. His humor was biting, even vicious. He would tell a bride she was ugly, make jokes about the groom’s dead mother and round things off by belittling the guests for giving such worthless gifts. Much of the badkhn’s humor was grotesque, even scatological.
t’s that same self-deprecating tone that characterizes the Yiddish-inflected Jewish jokes of the 20th century, Gordon points out. Who is the surly Jewish deli waiter of Henny Youngman fame if not a badkhn, making wisecracks at the customer’s expense?
“Even today, almost all Jewish entertainers have badkhn humor," Gordon said. "Sarah Silverman is completely badkhn. What did my father find funny? Dirty jokes. Because that’s the badkhn humor he grew up with.”