WHAT THE FUCK?
NO REALLY. WHAT THE FUCK?
ETA @ 10.17 EDT.
Actually, the more I think about it, the more I like the ending, which feels to me like a twisted, dark satire of a happy ending. The hero goes through battle, he loses a lot, but in the end, he comes up to the love of a good woman. Very traditional happy ending.
Of course, this is SPN, which likes to take traditional tropes and mess with them a little. It was definitely a weird place to leave off for summer hiatus, but I don't think this was supposed to be an honest-to-god happy ending for Dean.
I hope. If S6 has Sam and Dean working out of Lisa's garage and coming home from the hunt in time to catch Ben's soccer match, I will be PISSED OFF.
OTOH, if Lisa is killed off to motivate Dean to get revenge...I will also be PISSED OFF.