Castiel: Why do you hate this world enough to burn it to the ground?

Michael: Because I can. Because... Me and my brother... my Lucifer... when we fought in my world, we thought that God would come back, give us answers... why He'd gone, what we'd done... but, instead, do you know what happened? Nothing. No God. Nothing. And now... now that I'm in here... now I know why. God... Chuck... is a writer, and like all writers, He churns out draft after draft. My world? This world? Nothing but failed drafts. And when He realizes that they're flawed, He moves on and tries again.

Castiel: No, that's not how... Why would He do that?

Michael: Because He doesn't care! About you, me... anything. Now, at first, I thought I'd do it better. Show Him. Be more God than God. But now... I just want to burn every one of His little worlds until I catch up to the old man.

Castiel: And then what?

Michael: Even God can die.