Something I've been contemplating lately: are there truly "bad" people in the world? I'm thinking that the obvious answer is yes, although that's yes with a caveat.
First and foremost, I suggest that we strip away the "lunatic mass-murders" from the equation. There goes the likes of Kim Jong Il, Adolf Hitler, George Banks and such. Why? Because I'm thinking in those cases you are dealing with people who really aren't functional human beings; they are individuals so flawed that they probably don't have the same mental machinery as you or I do floating around in our collective skulls. Someone like Hitler was so different that he was probably human in genetics only. Note that I'm not giving him (and the others) a pass, but rather I'm suggesting that they are above and beyond simply being "bad". These folks are evil.
Second, we have to consider the scope of this thing. George Carlin once commented that there were no "...bad words. Bad thoughts. Bad intentions...", which rings true for me. We all probably have bad thoughts...I know I do. As for bad intentions, well I suppose that goes along with bad thoughts: are you bad for having them or bad for acting on them? It seems to me that "intentions" takes the notion of a thought one step further, in that it seems to represent a motive behind an action (in other words you have already done something). So I'm going to conclude that bad thoughts are relatively common, but bad intentions are far less common.
Third, we have to consider just what constitutes "bad". Is this a going against societal norms kind of thing? It can't just be a matter of religion defining what constitutes bad, as different religions have different views on this kind of thing. Equating the concept of bad strictly to a religious morality perspective basically ties you into a "I worship the RIGHT God but you don't" circular argument, which gets you nowhere. Case in point: divorce. The Catholic Church considers divorce to be bad (and I quote , "Divorce is a grave offense against the natural law." Citation HERE). That seems mighty "badish" to me. Then again other organized religions, even ones fairly close to the Catholic Church in terms of rituals don't have nearly such a "badish" attitude on the subject (and I quote, "While the Episcopal Church believes that marriage is a sacrament intended to be life-ling, the Church recognizes that situations exist where civil divorce or annulments are necessary." Citation HERE). On the other hand there are some fairly universal things considered to be bad, such as theft, murder, inflicting intentional harm of someone, assault, etc. I'm going to conclude that while there some gray area in the the definition of what is considered "bad", there is also some basic agreement as well. Maybe, just maybe, a definition for bad could be something like this: it is an action where the motivation is purely self-interest but which in the pursuit of that self-interest inflicts substantial harm on others.
In totality I do believe that there are bad people out there, namely people who personally act in ways that intentionally cause harm to others for sole benefit of themselves. They aren't mass-murders, and maybe in their own minds what they do is somehow justified, but never they less the harm they inflict outweighs any benefit created. That's a sad thing to conclude, especially for someone such as myself who was raised to believe that people are good. People are good. However, sometimes conditions and circumstances make good people do bad things. In the end it's maybe the sum total of those bad things vs the sum total of the good things that really determines whether or not someone is a "bad person".