Specially because I remember this quote from episode 5x10, Lucifer and Cas talking...
Lucifer: We're the in the same side (...) So, why not just serve your best interesting which in this case just happen to be mine?
Castiel: I'll die first.
Lucifer: I suppose you will.
*cries from fear*
But let's talk about favorite quotes, as in Dean/Cas moments!
When you see this message, post in your journal with your favorite Season 5 SPN quote.
Dean: Pretty nice timing, Cas.
Castiel: We had an appointment.
Dean: Don't ever change.
From Episode 5x04.
And we don't like future Human!Cas, but I love when he laughs at past!Dean and defend himself with "What? I like past you!.