Oh, but part of what I enjoyed was that you can see how it all goes wrong - there are so many what ifs and if onlys. If only Cas had spoken with Dean instead of going with Crowley, if only he had admitted to bringing Sam back up front. If only Dean (and Sam) had stopped thinking about their own immediate problems long enough to actually think about what Cas was telling them - though to be fair, Crowley was cheerfully distracting them with monsters and monster hunting and threats, and those boys could get distracted by random ghosts while in the middle of preventing the Apocalypse, so...

It is a tragedy. You can see it unfold step by step. You want to smack the boys over the head along the way as every good intention goes foul and every choice is wrong. And in the end it goes as all tragedies must. And I enjoyed it.

And now I want a season 7 of the boys having to serve outer god!Cas / lead la resistance / save Cas from himself. But maybe that's just me :-)