When Rabbi Shmuel of Nicholsberg and Rabbi Pinchas, author of Hahaflaah, came to Rabbi DovBer, the Great Maggid of Mezherich, they asked him how it is possible—as the Talmud commands—to "bless God over bad fortune just as one blesses Him over good fortune," and what is more, to do it "cheerfully."
The Maggid pointed to Rabbi Zusha of Anipoli, who was sitting in the study hall, and said, "Ask him."
They posed their question to Rabbi Zusha, a lifelong pauper, sick in body and afflicted with countless troubles, who replied, "I don't know why the Rebbe sent you to me, a person who has never had a bad day in his life!"
This same Rabbi Zusha was once reduced to such poverty as to lack bread, and when he was very hungry, he turned to God and said: "Master of the Universe! Thank you for giving me an appetite."
–Rabbi Adin Steinsaltz
From Opening the Tanya, p.283, by Rabbi Adin Steinsaltz