Dean Winchester: I wish we never took this job. It's jacked everything up.
Sam Winchester: What do you mean?
Dean Winchester: Think about all the hunts we went on, our whole lives. What if we killed things... that didn't deserve killing? I mean, the way Dad raised us...
Sam Winchester: Dean, after what happened to Mom... Dad did the best he could.
Dean Winchester: 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 Winchester: You didn't kill Lenore.
Dean Winchester: No, but every instinct told me to. I was gonna kill her. I was gonna kill them all.
Sam Winchester: Yeah, Dean, but you didn't. And that's what matters.