" In any human endeavor, some fraction of its practitioners will be motivated to pursue that activity with such concentrated focus and unalloyed passion that it will consume them utterly. One has to look no further than individuals who feel compelled to devote their lives to becoming concert pianists, say, or climbing Mount Everest. For some, the province of the extreme holds an allure that’s irresistible. And a certain percentage of such fanatics will inevitably fixate on matters of the spirit. "

― Jon Krakauer , Under the Banner of Heaven: A Story of Violent Faith