If anyone had reason to be bitter at God and existence, it would be
Aleksandr Solzhenitsyn. He suffered terribly in a Soviet labor camp and then from cancer. But instead of dwelling on vengeance, Solzhenitsyn “opened his eyes” and marveled at people’s noble behavior under horrifying circumstances. He even asked himself hard questions, like whether he had contributed in some way to his own suffering. He looked for failures in his own past and thought about how to rectify them now. He channeled much of this soul-searching into writing
The Gulag Archipelago, which ultimately helped undermine communist tyranny in the Soviet Union.