Sam: I May Not Be The Greatest Catch In The World, But I Don't Think I Should Just Settle. Cas: I'm Not

Sam: I may not be the greatest catch in the world, but I don't think I should just settle. Cas: I'm not telling you settle, Sam, but you're not going to be happy if every time you discover a flaw in somebody, you go to somebody else, because that somebody else is going to have their own flaws! Nobody's perfect!

Sam: You are.

Dean:

Cas:

Dean: What? Cas? My Cas? *points at Cas* This?

Sam: Well, yeah. I think Cas is perfect.

Dean: Well you can't have him.