The Duality of Man?

Today I walked into a counseling session, where the counselor was lecturing the counselee about the impression that the counselee portrays, regardless of his awarenes of his portrayal. In other words, people are watching whether you want them to or not. And we work for a company that holds high standards.
One sentence caught my ear though, and though I am sure it went way over this 18 yr old's head, it sure stuck in mine. The counselor was basically saying you have to be one way or another. You can't be a good role model and a rebel at the same time. He said, "It's the duality of man. Like 'Full-Metal Jacket. You have to be one way or another."
Wow. The duality of man. Images of joker wearing a helmet with a peace-sign right next to the "Born to Kill" slogan.
But in some ways, I am finding that we are all kind of dual. That was a major theme in Harry Potter 7. And I'd read a newspaper article arguing that J. K. Rowling's themes were blurring the line between good and evil. But I think it's true: the presence of love does not indicate the absence of hate. That's probably the most obvious of the duality point. Followed closely by 'having courage does not mean that you don't have fear.'
But this theme has been most revealing to me lately. Most on my mind:
Having confidence does not indicate the lack of doubt. Being confident doesn't mean uncertainty is eliminated.
I'd actually say that in trying times, when doubt reign supreme, those are the times where confidence is forged. You know that you may fail. You know that it might hurt. But eventually you learn to trust that you'll adapt at the right moment. Feel the right choice and act upon it. You learn to be confident. Full of fear that you will fail. But confident that you'll figure it all out along the way - emerge victorious.
Anyways... that's what I'm thinking. The duality of man.