Well, this is quite the interesting topic I will admit.
A while back I saw an expirement that was tested upon children. It looked at the behaviour of children in comparison to animals, henceforth dogs/cats etc.. 'playing' with eachother roughly, as they do. But at the end of the whole experiment it showed that humans were by far a bit 'worse' henceforth, the most prominent of what I saw popping to mind was 2 children in kindergarden, 1 of them wanted a toy because..well...the other one had it. He was stronger, so he went over there and kicked his duplo castle and took it. Of course on one side one can say 'hey..that was a dick move.', but nevertheless on the other, we are speaking of a young child. Yet nevertheless, I dont think people are generally 'evil' or 'good', every person is a product of their environment and upbringings in my opinion. If someone lives in a wartorn area where the person was accustomed to death and despair and learned that the hard way, also via their parents, Ill say (on an estimate) 9 out of 10 will also go down that same road. Just as the fact that those people (particularly males) who grew up in an abusive household with the father figure being abusive towards the family, has a higher chance of also being abusive via statistics.
So to my belief if people are generally good or bad, Im going down the middle line saying 'neither'. Each is brought up in a different way, told right from wrong through their parentage and that is what they are 'meant' to believe. On the flipside of course, each forms their own belief as they mature, it pends on how deep that heritage has been rooted into their brains. Just as a simple comparison to relate to what I wrote, my parents are both catholic, and do believe in that stuff for instance. Myself, I believe in a god, but not as its represented by the catholic church, so I 'dont' believe in catholism, but on the other hand I also didnt go 'all too far' from the path I was taught as a child, seeing as I do believe in the rough 'sculpture', Ill say, of the catholic church and being monogomistic believing in 1 god 'partially'.
End of the rant, my belief, people arent good or bad, each is a blank slate. Actions, what was taught, the environment and the treatment that person recieved forms the mold that will form that persons personality of being either goodhearted...or a total douchebag.