Philosophical and socio-political discussion on what determines whether something is "good" or "evil" aside, I believe humans are born "neutral". By that, I mean, upon the moment of our birth we are effectively emotional and intellectual blank slates. We're effectively "nobody". Our brains aren't developed enough for us to even have concepts of "good and evil". It's our environment and the way we develop genetically that determines what we become.
While most of us try to do the right thing, I firmly believe that everyone, under the right circumstances and given the knowledge of pure anonymity, can and will be a jerk. It's a natural response to our environment and our genetic heritage. We've spent thousands of years having everything in nature trying to kill us. Acting like a jerk is often a defense mechanism. One usually driven by fear. (not always the case, of course. some people are just assholes)
Baradiel said:
The whole nature vs nurture argument, combined with the ever changing perception of right and wrong/good and evil.
Short answer: no.
Slightly longer answer: Apart from good and evil being society's way of labelling things to make them easier to understand, I'm firmly in the Nurture camp either way. Your personality isn't planned from your birth, and your position on life's karma meter is neutral at birth.
I agree, except that I'm equally on the side of nature. You can surround someone with any kind of environmental stimuli you like, but their inherent genetic make-up will determine how they perceive those stimuli.
Think of it as wearing sun-glasses to see a movie. Regardless of the topic matter or look of the film, you're going to see it as dark. You'll see any movie as dark. This won't stop the movie from effecting you in some way, but it will effect how that information is filtered in and will leave an impression on top of anything the film does to you.
So, I've always believed it's a combination of both factors. The environment we live in and how our genetic makeup causes us to perceive that info through a filter. With enough effort, one can manipulate and/or overcome either, but in most cases it's both that determine who we are.