[Lith]

The insane seem to also fail to be able to ask themselves if their actions are rational (in short, if they are themselves crazy).

I do think Good and Evil exist, though I think in the real world the two can become so intermixed that you literally can't do one without a little of the other (especially where resources and courses of action are limited).

Reasons people commit evil acts vary; some do it inadvertently, some do it to get even, and some do it for no good reason they can think of, other than to see it happen. Apart from fiction, I don't think there are any people that are simply out to destroy the world. It doesn't pay, and you won't have much fun ruling a dead world. And if you destroy it, your work isn't complete until you destroy yourself, so in a sense, "ultimate" evil doesn't exist, because it implodes.

Your fictional character needs to want something, whether or not it is something we can relate to, though if we can relate, then it instantly makes the work more complex for the reader. And they need to want it badly. Jealousy, desire for glory, desire for power, hatred, selfishness (or the failure to see beyond your own desires or the effects of your actions on others)- all things we feel but are told not to embrace. And we either listen, or learn the hard way (sometimes).

Giovanna- and interesting post, though I would add that it is possible to feel guilt without having been told not to do something. When you see a negative effect your actions have had one someone else (suppose this gets into ability to sympathize, or have "same-feeling" towards another), even if the intended effect is even a good one. Or, as an example, a child taking a fish out of their fish tank, and then feeling bad that their fish died.

This reminds me of the experiment with the monkeys, and the rope with food at the top. Every time a monkey climbed the rope, a door opened inside the cage area and a hand pushed them back down. After enough time, the monkeys started pulling each other down off the rope, so they wouldn't get pushed. A monkey was replaced, and then another, until there were no original monkeys left, and no monkeys climbed the rope- they all pulled each other down, though none had ever been pushed off the rope or even climbed it. It's an example of conformity, but there was a real danger there at one point that they kept each other away from. But I'm starting to ramble.

Re: Martin- I would call Jon Snow and Sam (I forget his exact name) "good guys". They always try to do the right thing. (His last name isn't "Snow" for nothing.)