" That’s because we want to believe that people are infinitely complex, with millions of motivations and varieties of behavior. It is not so. We want to believe that with all the possible combinations of human beings and human feelings, predicting violence is as difficult as picking the winning lottery ticket, yet it usually isn’t difficult at all. We want to believe that human violence is somehow beyond our understanding, because as long as it remains a mystery, we have no duty to avoid it, explore it, or anticipate it. "

― Gavin de Becker , The Gift of Fear: Survival Signals That Protect Us from Violence