Castiel: Fight this!

Sam Winchester: Why? I'm happy in Charming Acres. We're all happy.

Castiel: Sam, I know you want to be happy. And I know what it's like to lose your army. I know what it's like... to fail as a leader, Sam. But you can't lose yourself. You have to keep fighting. You can't lose yourself, because if you do, you fail us. You fail all of those that we've lost. You fail Jack. Sam, you fail Dean.