Pardon Me Sir, but are You Just Cruel or Truly Evil?

What makes someone evil?  I think that all of us have some kind of evil held inside just waiting for the opportune moment to come out and say "Hello" to the world.  Others hold more than they can carry and others hold very little but is there some supernatural force that determines how much evil is inside of us?   Others may say it's not evil, it's just cruel.  Is there a difference?  In my book... Yes.

The Destructors by Graham Greene is full of evil actions and cruelty displayed by young children toward an old man who cares for an old house.  These boys or to be more specific, the main character Trevor, were not just cruel; they were evil.  For some reason they thought it wise to completely destroy this innocent old man's house.  What I don't understand is why.  They had a ball to play with and they had each other to provide entertainment; they didn't have to destroy this man's house.  Personally, I believe it all comes back to the "Evil v. Cruel" thing I was talking about earlier.

You can be taught how to be cruel.  Others can show you how to kick a cat or beat a dog or steal Twinkies; however, no one can teach someone how to be evil.  The "gang," as they like to call themselves, knew how to be cruel to someone but Trevor, the temporary leader, was born with evil in him.  He was horrid to the old man.  He didn't take money or valuable possessions.  He took the whole house.  That to me, cannot be taught.  Either you are born with a darkness inside of you that creates these ideas that just seem so right but are really so wrong.  Evil can help be apart of people's personalities.  It's impossible to take it away but it is possible to shelter it from the outside world until it drops in for a visit.  I understand the difference between the two, but can you?