Hillel the Elder faced many tests of his patience, but few were as deliberate as the man who came to him with intentionally absurd questions. The Talmud (Shabbat 31a) records that this man had bet four hundred zuz that he could make Hillel lose his temper — and he chose the most annoying strategy possible.
He came on a Friday afternoon, when Hillel was preparing for the Sabbath. "Why are the Babylonians' heads round?" he demanded. Hillel answered patiently. The man left, returned, and asked why the people of Palmyra have weak eyes. Hillel answered again. The man returned a third time with another irrelevant question. And a fourth. And a fifth.
Each time, Hillel greeted him warmly: "My son, what do you need?" Each time, the man posed the most trivial, insulting, time-wasting question he could think of. Each time, Hillel answered as though it were the most important question in the world.
Finally, the man revealed his wager. "I bet four hundred zuz that I could make you angry, and you have cost me every coin!"
Hillel's response was calm but devastating: "It is better that you lose four hundred zuz, and another four hundred after that, than that Hillel should lose his temper." The irrelevant questions were a test of character, and Hillel passed by treating each foolish question as worthy of a thoughtful answer. The sages derived from this that no question is truly irrelevant if the person asking it is treated with dignity.