Mockingjay Part 2 succeeded as an adaptation in that its ending scene was just as silly as it was in the book. It would have been fantastically poignant and sweet to end on “You love me, real or not real?” “Real” and fade out with hopeful ambiguity that maybe, even after all they’ve been through, our two young heroes are going to be okay, but instead it was deemed more appropriate to have a flash-forward to them picnicking in an idyllic field with their 2.5 children. Which is a strangely pervasive trend and one that, while kind of cute, is outweighed in most cases by the problems with it.
The other obvious big example of this is the Harry Potter epilogue, in which the characters we’ve grown to know and love return as adults to load their beautiful children onto the Hogwarts Express. A lot of people have a lot of problems with this ending, and I can see why, the largest two being that in the scene’s cyclical nature—complete with half the kids seemingly named after past characters—it creates a sense of repetition and almost stagnation. What are Our Brave Wizarding Heroes doing in the future? Oh, they’re dropping their kids off to go to Hogwarts, just like their parents did, and just like their parents did before. What are they doing career-wise? Are dark wizards still on the loose? Have muggle relations improved? How are they coping psychologically with the events they’ve lived through? A lot of the interesting business regarding the state of the world and its inhabitants after the story’s end is effectively shuffled to the side in favour of demonstrating everyone’s family trees.
Not to say that there’s anything wrong with a happy family as a happy ending, in fact it’s really kind of sweet to show that ordinary life goes on in a world torn up by magic or war. It’s just that it kind of comes across as the ultimate happy ending, where for many, especially if you’ve been through the kind of trauma and adventure only bestselling YA fiction can provide, you might not want to settle down and have 2.5 children. It wouldn’t stick out as an issue if every character from Harry Potter hadn’t appeared with a nuclear family, or at least some form of spouse and offspring, in tow, and especially if Katniss hadn’t stated multiple times that she never wanted to have children.
“I know it looks bad now, but trust me, in a few years we’ll be so happy together no one could possibly dispute it”
Because, you know, not everyone may want to have children, or even get married! Sure, they might think that now but genuinely actually change their mind in some years’ time, or they might genuinely actually feel that way for the remainder of their days. There is nothing wrong with either as it’s a personal choice, and in that it’s a choice, you shouldn’t enforce the ideal that a fulfilled life is a life where you have a conventional family structure. Yet I feel like these endings, to books aimed at and loved by kids and teenagers, especially, kind of play into that ideal. They show that the ultimate happy ending is marrying your (equivalent of) high school sweetheart and popping out a few babies, and never going on adventures again.
Not to say that these characters shouldn’t settle down—after all she’s been through, Katniss definitely deserves some stability. But it should not be equated immediately with being a loving wife and mother. I mean, hey, maybe sometime in her shell-shocked, PTSD-racked time spent living exiled and alone in the rubble of District 12 her natural protectiveness of small girls evolved into genuine maternal instinct and she decided she would like to raise a new generation and have a happy little brood, but since the reader/viewer never sees that and it’s tacked on as future epilogue, it’s a break in continuity with the Katniss we know.
It also feels, in the wake of The Hunger Games’ debacle of a love triangle subplot, like a very deliberate attempt to shut down the shipping wars. She chose Peeta, see? It’s impossible to dispute if they appear to be happily married with children many years later. This is how it ended, this is what their relationship became, no speculation or ambiguity allowed. The same could be said for Harry Potter of course, where as I mentioned, basically everyone marries and produces children with their love interests from the series. J.K. Rowling plotted out every bud and vine of the future family tree so there could be absolutely no speculation or argument about it, and no room for the readers to imagine and create and discuss their own stories and ideas about what happened after the end of the war. None of that silliness! Everyone got married and lived happily ever after, okay? Hush!
“Shh only dreams now”
Maybe that’s being too harsh, but it does feel a little petty to lock your readership out like that (especially when they’re going to write their own alternate endings anyway because they’re disappointed with yours) in an effort to erase all doubt. It’s almost harking back to the 19th century novel tradition of “Reader, I married him” endings, a final chapter that denotes that yes, all the couples that got together over the course of the story were married, Character X died miserable and alone in India and Character Y magically received a large inheritance and now everyone (who deserves its) is comfortably wealthy and great friends and the heroine is cradling her love interest’s infant son because that is the best place they could possibly be.
Sometimes ambiguous endings are an absolute pain, I admit, but sometimes a little bit of mystery combined with the potential for happy end—i.e. “Real or not real?” “Real”—is what thematically suits the story better. Peel back all the messages about propaganda and corporate sadism and bread and circuses, and The Hunger Games is a story about how war destroys people, but people will always find a way to survive. That’s Katniss’ story, anyway, and after all the Hell she’s been through I think the implication that she and Peeta are going to be okay together is heartwarming enough without absolute undeniable confirmation of it in the form of small children.
Especially when it feeds into the Voice of Society that’s already blaring messages at the readers—chiefly teenaged girls, who are the books’ and movies’ main audience—that they must conform to a certain standard of femineity and Achieve Their Biological Destiny. It tells them that, even in this escapist, far-flung fantastical world, the best sure-fire way for a woman to End Up Happy is if she settles down and has a nuclear family. What if the reader doesn’t want to have children? What if they physically can’t? What if they don’t want a husband and biological offspring because they don’t like boys? What if they don’t like anyone and are aromantic-asexual, which Katniss can easily be read as, thus giving readers of the same identity someone to relate to until this hetero-wonderful society-approved happy ending was stamped down as fact?
In the end I’m a sop at heart and love a good Happily Ever After as much as the next person, but I’d like to see happy endings that don’t necessarily involve a traditionally perfect family scenario, because if we keep using them it will become an unavoidable wall of a message pressing down on young readers. If you must cement the romance as unavoidable endgame, perhaps you could try to show that they have a functional relationship without children? Or perhaps, shock and horror, a protagonist who ended up single but was still okay because the platonic relationships from the series are still going strong? Or maybe don’t be afraid to leave the ending hopeful and hanging and looking out into a mysterious sunset? From time to time, at least?
And for the love of heaven, don’t have your heroine monologue emotionally about war and trauma to her baby, because as cute as it could be, it kind of just feels odd.
The Afictionado 
I actually liked the ending of Hunger Games, but I didn’t read it as a happy one. I read it as Katniss, even after everything, being broken and just going along with what is easier, what is expected. I haven’t read the books in a few years, but I don’t remember her seeming happy about how her life turned out, just resigned. Like she’s just surviving. And it shows how even if we all are disappointed in our parents’ generation for giving up and settling, that’s how even heroes end. So not happy or hopeful or healthy, but it struck me as depressingly realistic.