I mean, quite literally in season 5 they identified Dean as Michaels vessel and Sam as Lucifers.
So yes, theres always the formula of: Sam screws up, Dean has to fix it.
Well that, and Valentines Day.

Credit: Diyah Pera/The CW
So yeah, suddenly my Valentines Day plans are looking pretty good.
Right Now takes a shower, the guys head to Ohio.
So it looks like were dealing with a shapeshifter!
Well, at least until Stacy a.k.a.
the dead girl shows up and rips Dans heart out of his chest.
With that, most signs point to the wife, Melissa.
And yet, when Dean hands her a silver pen, she doesnt flinch.
So shes not a shifter, which puts us back at square one.
While Dean heads out to get some action, Sam stays home to research.
(Should we be worried about Sams lack of libido?)
Yep, its her dead husband Dan!
And fun fact: Pepper spray cant hurt him.
Neither can a potted plant.
Im sorry, you cannot tell me that someone looked at Dean and said the words dad bod.
Ill believe all the witchy high jinks you want, but I wont believe that.
By the time Melissa shows up at their room, shes finally ready to tell the truth.
Oh, and to make matters even more fun, the curse is transmittable.
Yep, thats our Dean.
More fun facts: Silver bullets dont affect whatever this thing is either!
But a chair to the head will knock it down for a least a few seconds.
And in those seconds, Sam, Dean, and Melissa go to find Sonya, the hairdresser/witch.
And no, thats not a euphemism.
Summing up much of the series is this interaction:
Melissa:What kind of FBI agents are you?
Dean:The fake kind.
Dont worry Sams stocked up on their witch-killing bullets.
Ill leave this one to Dean: Weve got to come up with a better name than that.
Inside, they find a book that explains theyre dealing with something called a Qareen.
For Dan, that was Stacy.
And for Melissa, it was Dan.
As for Sam, hes off to find the Qareens heart and stab it.
Brief pause here: What am I missing with this rock-paper-scissors bit?
What did Dean just win?
I swear I watched it twice and am just apparently an idiot.
c’mon help.
Amara … except its not Amara.
Its the Qareem presenting itself as Deans deepest, darkest desire!
(And to be literal about it, you cant get much darker than the Darkness.)
Only, this isnt really the Darkness.
Keeping that in mind, Dean is able to fight back.
But the real challenge is what comes next: Dean has to admit to his connection with Amara.
He has to tell Sam.
However, Sam is neither surprised nor is he about to blame or judge his brother.
After all, you dont have much choice when the sister of God chooses you.
Dean knows they need to kill the Darkness but he finally admits that he doesnt think he can.
I got it, Dean, Sam tells his older brother.
And lets just hope thats true.