Sam and Dean in “Unfinished Business”

Sam

You want me to debate you? This isn't even the real you I'm talking to.

Dean

Oh it's the real me alright, the new real me, the me that sees things for what they really are. Winchesters. Do-gooders fighting the natural order. Let me tell you something. Guys like me, we are the natural order. It's the way it was set up.

Sam

Guys like me still gotta do what we can.

Dean

Don't be so full of yourself Sammy. See from where I'm sitting there ain't much difference from what I turned into and what you already are.

Sam

And what exactly is that supposed to mean?

Dean

I know what you did when you went looking for me. And I know how far you went. Crowley told me all about it. So let me ask you... which one of us is really the monster, hmm? Starting to come back to you now.