What Is and What Should Never Be is likely to be one of the most meta'ed episodes in Supernatural if for no other reason than it'll likely be one of the few where we're so in a character's head. I've thought before of how interesting it would have been for Sam to be the Djinn's prisoner instead, simply because Dean's needs have always seemed so straightforward compared to Sam's, and Sam is actually the more internally mysterious character.
In his
commentary to the episode Kripke says that it is SPN's version of Normal Again. Yet in rewatching the Buffy S5 episode, Weight of the World, it strikes me that this is a much closer parallel. I hadn't yet heard someone mention an entirely different motivation for Dean's little head trip - guilt. Specifically, this exchange where Willow must enter Buffy's mind to return her from her catatonic state clicked my brain on (edited for emphasis)
WILLOW: Buffy, c'mon. It's your brain. Just tell me. What happened here?
BOOKSHELF BUFFY: This was when I quit, Will...Just for a second. I wanted it to happen... I wanted it over. This is - all of this - too much for me...I would grieve. People would feel sorry for me. But it would all be over. I imagined what a relief that would be. I killed Dawn.
WILLOW: Is that what you think?
BOOKSHELF BUFFY: My thinking it made it happen. Some part of me wanted it. And in the moment Glory took Dawn ...I know I could have done something better. But I didn't. I was off by some fraction of a second…I killed my sister…
WILLOW: All this - it has a name. It's called guilt. It's a feeling, and it's important, but it's not more than that, Buffy. Buffys. You've carried the weight of the world on your shoulders since high school. And I know you didn't ask for this, but you do it, every day. And so you wanted out for one second, so what?
BUFFY: I got Dawn killed ...
WILLOW: Hello! Your sister - not dead yet! But she will be if you stay locked inside here and never come back to us.
BUFFY: And what if I can't?
WILLOW: Then I guess you're right. And you did kill your sister.
BUFFY: Wait. Where are you going?
WILLOW: Where you're needed. Are you coming?
Of course the scene right after this ends the episode with Giles (the father figure) telling Buffy she must kill her sister for the good of the world.
In S2, Dean has been living with the burden alone in the first half of the season. When Buffy gets the news, she tells Giles:
"I *knew*. What was right. I don't have that any more. I *don't* understand. I don't know how to live in this world, if these are the choices, if everything just gets stripped away. I don't see the point. I just wish... I just wish my mom was here."
Like Dean and Sam, Buffy has lost her main parent this season, having lost her father earlier to neglect. Like Sam and Dean, the pressure for her to protect her sister and eliminate the supernatural threat that is out to get her has been building all season, and yet up to the last episode she has no plan, no clear weapon. Also like Dean, her sister isn't entirely what she seems to be and is the reason death and destruction is being visited onto those close to her.
It seems to me looking at the parallels that Dean's greatest wish isn't to see his mother again, or his family happy. It's to be able to lay down the burdens he has been carrying and is terrified he will fail at. Like Buffy, his reaction to being put in the place of Sam's guardian or executioner is to give up the life entirely, to "take a vacation." Of course, Sam gives him no choice, disappearing to find his own answers. Like Buffy, Dean's only vacation ends up occurring within his own head. Like Buffy, he recreates a world where his family is (for the most part) intact. Buffy remembers her parents coming home with the baby Dawn. Ironically, Buffy's "memory" of this happy scene is just as much a false construction as Dean's family tour. The event never happened. It's not hard to make a connection to Dean's own mixed feelings:
JOYCE: Are you ready to meet your new baby sister?
HANK: Oh c'mon now, Buffy... she's nothing to be afraid of.
YOUNG BUFFY: Who's afraid?
JOYCE: Don't you want to be the big sister?
YOUNG BUFFY: No, I wanna be the baby…
JOYCE: Like this. Support the head. There you go. We're calling her "Dawn."…
YOUNG BUFFY: I ... I could be the one to look after her sometimes, if you need a helper. Mom? Can I take care of her?
JOYCE: Yes, Buffy. You can take care of her.
How Dean actually felt about Sam joining their lives isn't something we know, but we do know Dean had come to love his little brother by the start of the series. But, of course, he had to give things up as well. Interestingly in his deepest wish he gets to be the "baby" of the family again, irresponsible and indulged by the rest despite his neglectful behavior, while Sam, the actual baby, is far away taking care of himself. Of course, like Buffy, the fateful change comes when he holds Sam in his arms, beginning a lifetime of duty.
Interestingly Buffy's next mental visit is to her mother's grave.
BUFFY #2: Death is my gift… It's what I do. C'mon, you've known me for how long? It's what I'm here for. It's all I am.
Joyce's final instructions to Buffy about Dawn are not unlike John's final speech to Dean, acknowledging the remarkable son he has had, and still asking for more even if he knows Sam may not be who they all thought he was.
JOYCE: No, listen to me. No matter what she is, she still feels like my daughter. I have to know that you'll take care of her, that you'll keep her safe. That you'll love her like I love you.
BUFFY: (teary) I promise.
JOYCE: Good. Good.
(They hug. )
JOYCE: Oh, my sweet brave Buffy. What would I do without you?
It's hardly surprising then that Buffy first stands by her mother's grave and then imagines herself failing her mother by killing Dawn. It is to her she made the original promise.
Dean's graveside speech to John is full of regret, talking about duty to others. Yet for Dean duty to others has always come after duty to his family, specifically to Sam. The audience has it hammered to them over and over again that Dean has one job, to protect his brother. The only reason he can make this speech is because in this world, that job doesn't exist. That's really Dean's deepest hope, that the job is no longer necessary and he can be free. But like Buffy, even though he only allows himself this thought in the deepest recesses of his mind, the guilt runs deep. And I think it's the guilt of wanting to be free that brings about his eventual return. Dean has no Willow to tell him to snap out of it, and return to the world where he's still needed. But though he manages the task, Sam's fate was already sealed - perhaps not by death at the Djinn's hand but kidnapped by the YED just the same.
Upon his return Dean confesses to Sam of how he wants things to be over, and even admits that the fantasy was never really that at all:
Sam: I thought it was supposed to be a fantasy.
Dean: It wasn't.
Of course, his decision to end his own fugue state and return to where Sam needs him all echo the moves Buffy makes in the last two episodes of S5. It's in the very next episode that both fail - Sam dies. Like Buffy, Dean is too late to save his sibling with anything but the gift of his own death.