I have so much to say about this show and how bad it is. If you want a excellent supernatural drama, then watch this BUT only from season 1 to 5. The fifth season's finale offers a great ending to the show and after that, everything is just plain bad. The plots stop making sense, they bring back characters just to kill them off and introduce new ones nobody gives a shit about. Think about everything that makes the show amazing, all those characters you love. Well, you'll be lucky if they decide to kill them off, because they managed to ruin Castiel and Crowley's characters to a point where I can't even stand them. Season 10's Crowley is just terrible, all he does is sit on his chair in his castle or whatever the hell that is (look i made a pun) and kill random demons. Regarding Castiel, a lot happens to him after the fifth season, sure, but his character just doesn't evolve. This is so irritating because i was such a huge fan of this show but now i feel like i'm gonna have to drop it.
I can only recommend the 5 first seasons, after that everything is just bad.
Just look at the gap between season 1-5 ratings and season 6-10 (or 11 now, since it has been renewed), and really the only people still defending this show are tumblr hardcore fans and shippers.