" killing is the ultimate expression of hatred and fear, as sex is the ultimate expression of romantic love and desire. And, as with sex, killing a stranger who has otherwise provoked no emotion is inherently unnatural. I suppose you could say that a man who kills a stranger is not unlike a woman who has sex under analogous circumstances. That a man who is paid to kill is like a woman who is paid to fuck. Certainly the man is subject to the same reluctance, the same numbing, the same regrets. The same damage to the soul. "

― Barry Eisler , A Lonely Resurrection (John Rain, #2)