I know there have been a lot of opinions about the ending of Carrie and I've heard a lot of people say they dislike it for several different reasons. But I'm here as someone who has read the book and seen & read literally every adaptation of Carrie to say why I think Mike Flanagan's ending for the first season was a great idea.
People say Emaline was unnecessary and that her possessing Carrie at the end to enact the prom scene takes agency away from Carrie.
I don't agree with this because of this simple fact: Carrie is the one who CHOOSES to give Emaline control during the prom. She already knows that Emaline is violent and willing to do violent things up to and including murder if it means she "gets even". She mentions several times to Carrie that she would like to see Carrie harm others. So when Carrie gives Emaline control during the prom scene, she knows full and well what Emaline is going to do, but feels like because it's Emaline doing it and not her, she is absolved from guilt and the death of her other classmates. This is a story about how people believe that what they are doing is 100% justified or "not that bad" because hey, those people deserved it, right? And Emaline uses that logic to convince Carrie to finish off Chris herself. Carrie is not innocent in the climax of this story. She is simply allowing the destruction to happen because like Emaline says after Carrie kills Chris, "You did nothing wrong. You didn't break anything but shackles."
And what's even more brilliant is how Flanagan twists that logic back onto the audience. How many people watching the show cheered or laughed when the phones exploded into students faces? How many watched just hoping for the moment that Chris would get the axe? I mean...they deserved it, right? That's what they get. I mean, sure a lot of them didn't even know about the blood or even take part in Carrie's bullying, but that's what they get for laughing at her suffering, for filming her. They all had it coming...right? "I'm not doing anything wrong by laughing at them because I would be the one rooting for Carrie. I'm one of the nice ones who would NEVER do something like that."
It's the same logic people use on the Internet and in real life every day. How many videos have skyrocketed in views of someone falling and hurting themselves? Of someone doing something embarrassing or stupid? How many videos have people watched about "fails" or "public freakouts" or "instant karma"?
And it's fine right? Because those people deserved it...right? And besides even if they didn't deserve it it was still funny...right?
Emaline (like every antagonist in this show) is basically the embodiment of that logic, just on a more destructive scale. She literally calls all of the people around Carrie "NPCs", like they're just characters in a video game and not real flesh and blood people. She is the disassociation of people's humanity that is used to justify cruelty and violence. Just like Chris, she thinks "you did this to me, therefore I have the right to do this to you." Just like Margaret, she thinks "they hurt Carrie and therefore must be made to suffer. And Carrie is too nice to do it so I have to do it for her." Purely eye for an eye logic. And now, just like Chris and Margaret, she is influencing and manipulating someone who can unleash disasters of monumental proportions in the span of an hour or two with a single thought.
Just like Stephen King did at the end of the novel, Mike Flanagan is contemplating the implications of what this ending means for the entire nation. What does it mean now that we have someone with that level of power unleashed upon the world? What happens when that person is rejected, made an outsider? What happens when cruelty and violence is seen as the logical response to strangeness, to otherness? And what happens when that outsider, that person with that level of power, reflects that logic back on to us?