Supernatural, Season 2

Dean:
Think about the hunts we went on,Sammy, our whole lives.

Sam:
Okay.

Dean:
What if we killed things that didn't deserve killing? I mean, the way Dad raised us-

Sam:
Dean, after what happened to Mom, Dad did the best he could.

Dean:
I know he did. But the man wasn't perfect. And the way he raised us to hate those things? And, man, I hate them. I do. When I killed that vampire at the mill I didn't even think about it. Hell, I even enjoyed it.

Sam:
You didn't kill Lenore.

Dean:
Well, but every instinct told me to. I was gonna kill her, I was gonna kill them all.

Sam:
Yeah, Dean, but you didn't. And that's what matters.

Dean:
Yeah. And because you're a pain in my ass.

Sam:
I guess I might have to stick around and be a pain in the ass, then.

Dean:
Thanks.

Sam:
Don't mention it.