One of my favourite moments of Castiel. It’s one of the first times he seriously defies Heaven’s orders. And he’s so good at it. What do you mean Castiel can’t understand subtlety? He misses pop-culture references and most forms of sarcasm, though this relaxes the more time he spends in human culture. The best thing I think is that at the end he isn’t shy or all mysterious about it; he looks Dean in the eyes with reassurance and trust in him - it’s very telling where his alliance truly lies, even then. No wonder Heaven dragged him back up just two episodes later.