A congregant asked his rabbi, “Rabbi, you’re a man of God. So why is it that you are always talking business when I, a businessman, am always talking about spiritual matters when I’m not at work?”
“You have discovered one of the principles of human nature,” the rabbi replied.
“And what principle is that, Rabbi?”
“People like to discuss things they know nothing about.”
From Oy! The Ultimate Book of Jewish Jokes, by David Minkoff