Supernatural2005

Sam Winchester:
You know what, Dean? I saw what happened back there. You coulda killed that guy and you didn't. You took mercy on him.

Dean Winchester:
You call that mercy? Imagine you spend your whole life huntin' down the guy that knifed your father. When you finally find him, he whips you like a dog. [Smiling, with deep satisfaction] How do you think that feels? That kid's gonna spend his whole life knowing that he had his shot and that he couldn't beat me. [Softly] That ain't mercy. That's the worst thing I coulda done to him. And what I'm gonna do to you, Sammy... Well, that ain't gonna be mercy either.