The psychiatrist M. Scott Peck wrote the best seller The Road Less Travelled. As a psychiatrist it's his job to try and understand what makes people tick. Here's what he says in another book, What Return Can I Make:
"Sin has not been a very fashionable word these past few years...It would seem the doctrine of the day is that all that is needed in this world is a little more affirmation. I'm OK, You're OK is the title of one of the leading pop psychology best-sellers. But what happens if I'm not OK?... The reality is that this world is not all OK. Evil is not the figment of some medieval theologian's imagination. Auschwitz and My Lai and Jonestown are actual places and actually happened. Human evil is real.The reality is that we do betray God and ourselves and each other. We do it routinely. The worst of us do it blatantly, even compulsively. The noblest of us do it subtly and self-centeredly, even when we think we are not trying to do it. Whether it is done consciously or unconsciously is of no matter; the betrayal occurs."