However cruel Attila, Genghis Khan and their followers may have been, the act of killing people personally, face to face, must have been unpleasant to them, and the consequences of the murder still more unpleasant: the wailing relatives and the presence of the corpses. And thus their cruelty was restrained. Nowadays we kill people through such a complex process, and the consequences of our cruelty are so carefully removed and concealed from us, that there is no restraint on the bestiality of the action. The cruelty of some people towards others will continue to increase until it has reached unprecedented dimensions.

What is Religion? by Leo Tolstoy