(This article contains some spoilers)
Supernatural started out with fairly black and white categories of what good and evil were with hunters on a mostly good side taking out heartless monsters. It only got murkier from there on, with these hunters letting sweet seeming werewolves off the hook and playing Dr. Phil to the King of hell himself and the season ten finale ending in some of the most difficult choices there have been on the show.
Season ten has mostly been about doing something about the Mark of Cain on Dean’s arm, because the mark dehumanizes Dean and makes him extremely violent. By the finale Dean has called Death into the picture, and Dean’s main choices are a) locking himself away where he can’t do any harm and kill his younger brother (who if left alive would not stop looking for a cure and thus won’t let Dean stay locked up) b) keep dealing with the mark and get rid of Death.
Supernatural presents us with a very difficult conundrum: to kill the one you love more than anything else alive and lock yourself up to save the world from yourself. Or to keep suffering, being dangerous to and get rid of Death. What would you choose? Could you choose between love and preventing destruction that you are causing? Dean looks at the destruction he is causing, at the monster he has become and is ready to give up his freedom for peace, answering Cass’s question form ‘Swan Song’ (about what Dean wants more: freedom or peace?) a bit differently than before. He is ready to give it all up, even his baby brother. But suddenly he kills Death instead of his brother, leaving some of the audience a little stunned. An even more shocking feeling for me was the fact that I was deep down rooting for Dean to kill Sam or at least to lock himself up. I was not rooting for him to make a reckless decision and stop being the comparatively more reasonable character he’d been this season when it came to taking decisions about the mark. There seemed to be a jump that I could not see, a jump that changed Dean’s entire thought process. Why was I thinking this way though? Hadn’t I always wanted the brothers to stick together? Maybe it was because I’d finally realized the price they were paying for each other’s love and well-being that made me wonder what price is too much. Yes, they chose each other, but we are left wondering if that choice was theirs to make and if it was any good.
Another really interesting moment in Supernatural was when it made one of the most evil beings on the show say ‘I just want to be loved’. It succeed in showing us the human side of a despicable creature. Showing that deep down even these monsters want the same thing as humans: love.
Supernatural succeeds as a thought provoking show because it questions the audiences’ beliefs and keeps asking questions of right and wrong in almost every moment. And the thing is it does not always provide its audience with the ‘right’ answer. Should Dean have allowed that fellow hunter to die so easily? ‘Of course not!’ many of us might instinctively scream, but that’s why the show works, because it does not always make its characters choose the right path. Also this show inspires a lot of loyalty and interest as evident by the fandom with people always coming up with a relevant gif from supernatural to any post on tumblr. The fandom’s presence shows that people are very invested in the decisions the characters make and therefore it succeeds in producing such analytical inquiry by the audience.
 Crowly in Season 8 Finale
 Rudy in Season 10 Finale