I don't envy any showrunner who has to write a series finale, especially after observing the very different reactions over the past few days to the final episodes of "Two and a Half Men" and "Parks and Recreation."

Consensus on the former seems to be outrage mixed with bafflement, while response to the latter seems to have been copious tears mixed with warm fuzzies.

Looking at both finales, however, it appears each long-running sitcom ended with an episode that was true to what the series was about. The literally cartoonish "Two and a Half Men" finale, which (spoiler alert) wrapped with pianos being dropped on both the characters and on creator Chuck Lorre, was a fittingly nihilistic send-off for a show that seemed to find all its characters loathsome and had little regard for the humanity of any of them, except insofar as Lorre could use them for punching bags and punchlines. Meanwhile, the "Parks" ending, which borrowed a page from the "Six Feet Under" finale and showed flash-forwards of the characters' distant futures, stayed true to the show's earnest message: when you work together as a team, everyone benefits.

Sure, critics complained that the "Men" finale spent too much time rehashing Lorre's behind-the-scenes clashes with Charlie Sheen, who's been off the show for four years already, and who declined to return for a farewell episode so relentlessly devoted to degrading his character. But then, this was a series where everyone was degraded. "Men" spent 12 years pushing the envelope on acceptable topics for family-hour comedy (yeah, it pushed the envelope downward, but it did push it). And in the finale, which was full of characters breaking the fourth wall to comment on the show's admitted crassness, and which contained an animated flashback sequence, the show pushed the envelope in form as well as content. With Lorre having spent 12 years lampooning these characters as crudely as possible, did critics really expect him to start pretending now that he cared (or that viewers should care) how their narrative journey wrapped?

Even "Parks" earned some critical grumbles as it hit the home stretch. Critics complained that the final season has been one long flash-forward (taking place in 2017) and extended farewell, with each character getting an episode to wrap his or her storyline. Elements of the season felt contrived (like the last-minute conflict between Leslie and Ron). The whole season seemed like a drawn-out funeral for someone not quite dead yet, heavy on the tears and light on the laughs, playing out like the last hour of "The Lord of the Rings: The Return of the KIng," with one climactic goodbye after another. And yet, how else would you expect the show to go out? The series created an elaborate fictional universe in Pawnee, Indiana, a small-town community populated with vivid eccentrics who were also recognizably human in their desires, fears, and dreams. It took some time and preparation to give everyone their due; the series' heart-on-its-sleeve sincerity all but demanded that.

The complaints about both shows' finales stem from more than just the flaws in those last episodes. They're a natural by-product of the problematic nature of any TV finale. As longtime viewers of a series, we ultimately want to feel like we haven't wasted our years-long investments of time and emotional energy. We remember how we felt at the end of, say, "Seinfeld" (where the finale suggested that we were chumps for liking these moral monsters for so long), or "Dexter" (he becomes a lumberjack? Really?), or "How I Met Your Mother" (who conveniently died shortly after viewers met her, just so Ted could go back to Robin after all these years?), and we bristle at the notion that another series ending might make us feel the same sense of frustration and outrage.

But it's no easier for the writers. They're working in a medium built on open-ended narrative, one that's not designed for closure, Over the years, showrunners have tried to confront this inherent difficulty. David Chase simply refused to provide closure in "The Sopranos" (though you could read the infamous blackout ending as an acknowledgement that Tony would never feel secure, that he'd always be looking over his shoulder at the likely possibilities of arrest or assassination, and that this was how he'd have to live the rest of his life, which might just end in one more moment). Damon Lindelof and Carlton Cuse explained many of the mysteries of "Lost" in the final episode, though not all of them, and (as they surely knew) not enough to satisfy everyone.

Still, the notion that every show has to wrap in a tidy package that ties up all loose ends and offers viewers a cathartic sense of closure persists. Which is curious. Not just because such a finale is nearly impossible to write, but also because of the vogue over the past-decade for innovative, antihero-centered shows that offer no promise of moral uplift or just desserts. That other HBO saga of Jersey mobsters, "Boardwalk Empire," ended last fall with the murder of protagonist Nucky Thompson, and that definite sense of closure was far less satisfying than the ambiguity of "The Sopranos." True, "Breaking Bad" creator Vince Gilligan did figure out a way to satisfy viewers' contradictory impulses to see Walter White both punished and redeemed, but that finale seems more the exception than the rule.

There are precedents, though, for crafting a finale that is both open-ended and climactically final, and both "Two and a Half Men" and "Parks and Recreation" drew upon these precedents. "Men" seemed to take its cue from the "Seinfeld" finale, whose point was, in part, that the show's characters had neither learned nor grown in nine years and were left stuck in the same pointless conversation that they were having in the pilot episode. "Parks" borrowed not just from "Six Feet Under"'s flash-forward finale (which implied that the characters had full lives yet to lead, even while showing us how each of them would die, which made sense in a series about death), but also from the last episode of "M*A*S*H." That, too, offered a seemingly endless series of individual adieus (the episode ran two and a half hours and was titled, "Goodbye, Farewell, and Amen"), which seemed fitting after 11 seasons spent with many of them, while hinting at the future each character would face as veterans of the Korean War. The "M*A*S*H" finale was the most-watched episode of scripted television in American history, so it must have done something right.

To the extent that the finales of "Two and a Half Men" and "Parks and Recreation" built on those precedents to wrap the series in a way that was true to each show's world view (cynicism and optimism), that reflected the way each show insisted on operating by its own rules, and that offered a sense of finality without filling in all the blanks, both endings have to be considered successes. And if we wanted more from these finales, maybe we should ask ourselves why we watched these shows for so many years, and what emotional needs they fulfilled for us.