Good vs. Bad

"Nothing is easier than to denounce the evil doer; Nothing more difficult than understanding him."
-Fyodor Dostoevsky

I have a suspicion that every single human on this planet has some good in them. This isn't a theory many people agree with. Usually when I announce this, a common retort is "Well what about Hitler?" My response? Hitler loved his mother. I firmly believe that there is no true evil on this planet. Of course I think there are evil deeds, but fully truly evil people? I don't think so.
What goes with that is the idea that there is no true good, unless I suppose you are the next Messiah. Which in that case I suggest you market that skill, there should be a media frenzy and People magazine would be sure to give you a full cover story. Other then that though, there are no people who are purely good. No one is put on this earth as a perfect individual. To be good at everything, or to always treat people correctly. They have to learn that skill through time and experience.
Humans are capable of extreme evil towards one another, I will not deny that. And I will not deny that humans are also capable of extraordinary things. A person is a mix of both, some are mixed evenly and some have more good then evil, and some vis-a-versa. Oh, and Hitler also loved dogs.