Comic stips raise interesting questions...

I was reading this comic strip the other day. It started to make me think about the answer myself. If your eyesight really sucks and you cant read that it is basically calvin asking hobbes whether people are good with bad tendencies, bad with good tendencies, or just crazy. I have wondered for a long time about this question.
    A persons personality (I think) basically derives from their upbringing. Would this mean that people are kind, generous,hardworking etc. and with every mean comment or action towards them they lose these qualities or are they mean, stingy,lazy etc. and with every nice thing or care you give them they lose these faults and become better people. I'd prefer to think they're basically good but I think they are actually basically bad
   It's a scary thought to think that we are crazy as this could mean that every horrible genocide was just because someone felt like it. I could become a dictator and suddenly say "I don't like people who read blogs" and you would be dead.(Don't worry I won't kill you!)
  So which do you think, comment below.