Another thing I felt was important about this episode is that Cas stood by SAM. Cas has never really had much interaction with Sam and has point-blank blamed Sam. Yet here we have Cas calling Sam his friend and even assuring/comforting Sam by telling him that his death would not help.
YES. I've been waiting all season for that moment! I thought his "You are not taking Sam Winchester... I won't let you" in 5x10 was as good as we were going to get, so Cas actually saying outright that "Sam is my friend" completely blew me away. And Sam was so concerned for Cas every time he collapsed, aww. They're finally becoming buddies! (Although Sam still doesn't know it was Cas who let him out of the panic room...)
I have to admit, I was pretty ticked off by Anna especially since she kept saying "I'm sorry" right before she tried to kill everyone. I mean really? After everything she preached to Cas???
I actually loved that moment. Anna didn't WANT to kill these people... she seemed to have real feelings for Dean, after all. She just felt that it was the only way. Kind of like when Cas was about to kill Jesse... it was breaking his heart, but he felt it was the only way to stop him from killing all the angels. The outcome of that experience seemed to be what changed Cas, and he started thinking more like Sam and Dean after that. Anna never got that chance. I thought it was sad. She was still fighting on their side, but doing the dirty work she felt they were too loyal to their family to do, you know?
Guh, I loved this episode.














