" And morally, maybe, if there’s such a thing as moral exhaustion. There is such a thing, he decides. You start by being idealistic, morally strong if you will, but then the rock of your moral strength is eroded, bit by bit, until you’re, well, exhausted, and you do things that you never thought you would. Or you do things that you always feared you would. Or something like that. You’d think that there would be a breaking point—a decisive moment—but there is no single moment or event that you can put your finger on. No, it’s not that dramatic—it’s the dull, monotonous process of erosion. Maybe "

― Don Winslow , The Cartel (Power of the Dog #2)