Two people once made a bet that whoever managed to anger Hillel would receive four hundred zuz. Friday afternoon, while Hillel was washing himself in preparation for Shabbos, one of the men tried to irritate him.
He passed by the door of Hillel's house, calling out with chutzpah, "Is Hillel here? Is Hillel here?" Hearing him, Hillel dressed, went outside, and asked how he could help.
"I have a question to ask," said the man. "Ask, my son," Hillel prompted. "Why are the heads of the Babylonians round?" To which Hillel answered, "My son, you have asked a great question. It is because the Babylonians do not have skillful midwives."
The man left, waited a while, then returned, calling out once again, "Is Hillel here? Is Hillel here?" Hillel once more dressed and went outside asking how he could help the man.
"I have a question to ask," the man said. "Why are the eyes of the Tarmodiyim people bleared?" Hillel listened patiently and replied, "My son, you have asked a great question. It is because they live in sandy places."
The man left for a while, and returned a third time. "Is Hillel here? Is Hillel here?" Hillel put on his robe, went outside and asked, "My son, what do you require?" To which the man responded with another question, "Why are the feet of the Africans wide?" "My son, you have asked another good question," Hillel tolerantly replied. "It is because they live in watery marshes." The man continued roughly, "I have many questions to ask but I am afraid that you may become angry."
Thereupon Hillel sat himself down before him, saying, "Ask all the questions you have." As if he was unaware, the man asked, "Are you the Hillel who is called the Nasi of the Yidden?" "Yes," Hillel replied. The man retorted, "If that is you, may there not be many like you!" "Why, my son?" "Because I have lost four hundred zuz because of you," he replied. "Always be careful of your moods," Hillel answered. "You can lose four hundred zuz, and yet pay another four hundred zuz, but Hillel will never take offense."
(מסכת שבת ל"א ע"א)