Over two decades after its initial release, “Six Feet Under” is a uniquely of-its-time television show. The series about a family-owned funeral home and the dysfunctional constellation of people whose lives are shaped by it is often as emotional and riveting now as it was upon release, but it’s also aged in interesting key ways. With “American Beauty” scribe Alan Ball and future “Transparent” creator Joey Soloway working behind the scenes, the series also builds in space for existential contemplation, playful and shocking transgression, and mistakes. Lots and lots of mistakes.

As the show wears on, how frequently — and how believably — the Fisher family screws up is at times directly correlated to how well the show’s story succeeds. The writers of “Six Feet Under” put their characters through the wringer again and again in a move that makes the series’ weakest seasons feel redundant, while its high points mine the mess-ups for heartfelt emotion, relatable ambivalence, and fantastic drama. Ultimately, “Six Feet Under” is about humankind’s search for meaning, something its characters scramble towards for five full seasons before the show’s emotionally leveling series finale puts all their mortal angst into perspective.

Today, “Six Feet Under” is most remembered for its ending, as it should be: “Everyone’s Waiting” is a life-changingly great series finale. Still, it’s worth looking past the show’s last episode to what came before, to figure out once and for all which seasons of the show are masterpieces and which (if any) are better off dead and buried.

5. Season 4

At its worst moments, the fourth season of “Six Feet Under” feels like it’s asking for absolution. The show speaks often of afterlives and higher powers, and as viewers watch helplessly while the Fisher family trashes much of the happiness and self-awareness they’ve spent years building up, it feels as if “Six Feet Under” wants to cast us as the absolvers. “Can you forgive these characters for being the absolute worst for the twentieth time in a row and learning nothing from their mistakes?” the show seems to be asking. It’s tempting to answer “no.”

In season 4, mortuary worker Rico (Freddy Rodriguez) half-heartedly cheats on his wife, angrily rationalizing it the whole time. Plus, eldest Fisher son Nate (Peter Krause) falls into the same toxic pattern by once again trying to make things work with ex Brenda (Rachel Griffiths) despite the fact that she’s already in a healthy relationship. There’s nothing wrong with an infidelity plot, but “Six Feet Under” is lousy with them, and by season 4, the show’s writers’ room has gone back to the same well too many times to make an impact. Elsewhere, matriarch Ruth (Frances Conroy) gives up her newfound freedom to marry a strict, mentally unstable man, while Claire (Lauren Ambrose) ends a season of experimentation with a major backslide.

Despite the season’s exhausting, elliptical character arcs, it still features some phenomenal moments. The series pulls off a risky, truly shocking slow burn when it finally reveals what happened to Lisa (Lili Taylor), and its examination of Nate’s grief over her open-ended death leads to some of the series’ most profound scenes. A plot in which straitlaced Fisher son David (Michael C. Hall) gets “carjacked” over the course of a torturous, nerve-wracking episode also makes the bold choice to deal with trauma at length. The best parts of “Six Feet Under” season 5 take daring plots that most TV shows would contain to a single episode and allow them to sprawl out, making good on the old adage that healing takes as long as it takes.

4. Season 1

“Six Feet Under” starts with a bang, literally: a bus crash that kills Fisher & Sons owner Nathaniel (Richard Jenkins) on Christmas Eve. That inciting incident brings the Fisher family together under one roof again for the first time in years. Sons Nate and David attempt to sort out the family business, while newly widowed Ruth and teenage daughter Claire struggle to grieve. Much of the show’s first season focuses on the theme of appropriate and inappropriate mourning, and “Six Feet Under” quickly busts the myth that there is any one “normal” way to react when your world is shattered.

Season 1 is by no means bad, but for new viewers, it can be an acquired taste. “Six Feet Under” isn’t often included in conversations about prestige TV antiheroes, but it should be: the show puts in work to make each of its characters unlikeable, and rarely has any TV series cared less about getting viewers on board with its deeply flawed ensemble. Still, by season’s end, it’s impossible not to love the Fishers thanks to the show’s strong central cast and each characters’ relatable search for meaning. Plus, the season sets up the show’s most enduring and surreal plot devices: dead people who talk to the living (the season earns points for prominently featuring Jenkins as Nathaniel’s ghost) and opening scenes featuring the demise of a stranger.

For all its strengths, “Six Feet Under” features some dated attitudes that emerge early on, including on topics of queerness, consent, and mental illness. The hardest early series plot to watch features Billy (Jeremy Sisto), Brenda’s twin brother with whom she has a disturbingly codependent relationship. Brenda ultimately transforms into a multidimensional character, but in season 1, she comes across only as a practiced provocateur, while bipolar Billy is presented as unhinged, edgy, and dangerous. He’s not a bad character, but his breakdowns seem to be added in as needed to cause strife between Brenda and Nate, and his boundary-crossing behavior gets too much screen time.

3. Season 2

If season 1 of “Six Feet Under” establishes the show’s offbeat, taboo-busting sensibilities, season 2 is where it becomes clear that the series thrives not just on drama, but on glorious, impulsive messiness. It’s the season in which Keith (Mathew St. Patrick), a cop, shoots a man on the job and then comes by David’s house for a booty call. It’s the season that sees Brenda cosplaying as a sex worker, dabbling in increasingly risky sexual exploits that threaten to derail her new engagement to Nate. And it’s the season in which Nate learns that he has a potentially deadly brain condition, one he keeps secret from some family members until the tense season finale.

This is also a season of major growth, and in a rarity for the show, characters are allowed to flourish without dire consequences. Ruth especially finds a new lease on life, exploring self-help workshops and dating persnickety florist Nikolai (Ed O’Ross) before finally realizing her true calling as a grandma. It’s clear by this point in the show that Nathaniel’s death woke the Fisher family up, and that jolt of clarity and awareness is theirs to do with what they please. In some cases, they lean towards destruction, but in others, they find beauty and unexpected joy. More often than not, the two options aren’t mutually exclusive.

Season 2 has its shortcomings, most notably when its writers fail to reckon with obnoxious character faults that seem to exist in their blind spots. Keith, for example, comes across as a violent cop with anger issues who’s borderline abusive to both David and his niece. Yet the show regularly positions David as equally as deserving of criticism, and it’s frustrating to see the couple’s relationship drag on with its most obvious problems unacknowledged. Still, the season is compelling overall, with rewarding character payoffs, explorations of uneasy truths, and darkly hilarious client deaths that grow more ridiculous by the episode.

2. Season 5

In terms of sheer volume of tears, it’s possible that nothing on earth has ever made me cry more than the final season of “Six Feet Under,” and I’m not alone. The show’s series finale, in which Claire hit the road in pursuit of something new while the future deaths of each character play out one after another, is largely hailed as one of the best TV endcaps of all time. It’s funny, bleak, and almost incomprehensibly moving. It pulls together the disparate plot threads of a show that’s always felt somewhat meandering and creates an incredible mosaic of love and pain.

For five seasons, each of the Fisher kids struggled to find a point to life, but it becomes clear in the eleventh hour that the purpose was close to home all along. It’s death: you’re going to die, so you’ve got to live. The show portrays death with all the mystique and mundanity, dark humor and raw grief it deserves when it kills off Nate in an artful bait-and-switch nine episodes in. The hour that sees him survive a stroke and wake up from a coma, only to die during a quiet moment in the hospital, is also almost too painful to bear. It’s the most real-feeling portrayal of grief and shock this side of “Connor’s Wedding” and the “Buffy the Vampire Slayer” episode “The Body.”

Few shows have ever stuck the landing quite like this one, but “Six Feet Under” season 5 doesn’t earn the top spot on this list because it still has a few key weak points that are often glossed over thanks to that stunning finale. Claire’s character arc, for example, largely fizzles out as her series of punishing, misguided relationships ends with the liberal firebrand marrying a card-carrying Republican. The show also attempts to mine even more infidelity plots for meaning, and comes up empty. Yet the back half of the season is undeniably powerful, and the finale’s legacy may well outlive us all.

1. Season 3

“Six Feet Under” pulled off several perfect episodes — two whole years before “Everyone’s Waiting.” The show’s third season begins with one of the most beautiful hours in its entire run, a dreamy exploration of the Fishers’ lives after Nate’s brain surgery. Some storylines in the episode are imagined by Nate while he’s under the blade, while others — like his marriage to Lisa — are surprisingly real. Eventually, the family slips back into chaos, but the episodes following Nate’s surgery feel like a dividing line for the show, an era of relative tranquility and acceptance for a character whose impulse is usually to fight the future.

That sense of bittersweet peace continues throughout the season, including in the show’s most quietly touching cold open, “Nobody Sleeps.” In it, a gay man passes away peacefully in the middle of a movie night spent with his chosen family. He dies laughing, with his partner’s arms around him, in a warm room full of people he loves. “Six Feet Under” tries to dig into the concept of mortality again and again across its five seasons, but this scene is arguably its most effortlessly relayed thesis statement.

The season includes other surprising delights, too. It introduces Bettina, the no-nonsense caretaker played by Kathy Bates who becomes fast friends with Ruth, and Rainn Wilson pops up as an eccentric employee who also forges an offbeat relationship with Mama Fisher. Plus, in a rare win for Claire, the teen dodges a bullet when she learns that her teacher is an exploitative creep and chooses not to have a baby with a guy who doesn’t respect her. The season also ends with one of the most breathtakingly shocking and ironic moments of the show, as Nate is freed from his suffocating marriage by the news that his wife, Lisa, is dead. Every season of “Six Feet Under” is enjoyable, but the third season sees the show firing on all heartfelt, devastating, darkly funny cylinders.