Castiel isn't sure how he feels about Metatron giving him encyclopedic knowledge of nearly every form of fiction. Aside from not wanting to accept a gift from Metatron, it's made conversations with Sam and Dean more confusing sometimes. Before, he just ignored the references entirely; now he half-understands what Sam and Dean are saying which can be distracting when he doesn't understand the other half.
"Dean, why did you refer to me earlier today as a character from Dr. Sexy M.D.?"
"Because you were acting like her, Cas. It's a metaphor."
Castiel thinks over the response. He's pretty sure he understands. They're more like analogies in his opinion, but he does recognize a quote and opportunity to play the game too.
"Okay... Gus." He grins.
"What? Wait..." Dean holds up a hand to stop Cas from saying anything. He frowns, stares at nothing as he tries to remember who 'Gus' might be and what he has to do with metaphors.
Dean gives up, then slowly turns to look at Castiel again, eyes wide in horror.
"I don't understand that reference."
Author's note: It is a terrible reference, but it is Cas.