The brothers Rabbi Shmelke and Rabbi Pinchos asked the Maggid of Mez'ritch, "The Talmud (Brachos 54a) says that a person is obligated to bless the Almighty for misfortune with the same joy as when one blesses for good fortune. How is it possible to fulfill this obligation?"
The Maggid advised them to put the question before Rabbi Zushe who was extremely poor and lacked even basic necessities. Though he had many difficulties in his life, he was always happy. They went to the study hall where they found Rabbi Zushe, and told him the Maggid said he would explain how it is possible to bless the Almighty with joy over misfortune.
"I'm surprised that our Rabbi sent you to me about this," replied Rabbi Zushe. "You should rather ask someone who suffered some misfortune in his life. I have never experienced anything bad in my life. Only good things have happened to me."
(see Gateway to Happiness, pp.65-6)