Six Feet Under aired between 2001 and 2005, and it provides sweeping, expansive looks into the lives of the Fisher family, who own a funeral home in Los Angeles. The show is famous for beginning each episode with the death of a person whose memorial is held at Fisher Funeral Home. The show is also famous for portraying the dreams, fantasies, and inner monologues of each main character.

RELATED: Six Feet Under: 10 Hidden Details About The Main Characters

The series has one of the most epic and macabre finales of all time. It's only fitting that a television show about death would depict the ways each main character dies in its last five minutes. Despite this ending, the psychological and layered HBO series left some plotlines unresolved. All these years later, here are 10 unsettled narrative arcs that are still driving fans crazy.

The Death Of Lisa

Lili Taylor plays Nate Fisher's old girlfriend from Seattle, Lisa. When Lisa gets pregnant after having casual sex with Nate, they decide to marry. Their marriage seems doomed from the start, and Lisa eventually goes missing. Her car is found near the beach, but it's not until Season 4 that her body washes up onshore. Nate, a devastated and confused widower with a young daughter named Maya, fights Lisa's family to give her the burial she told him she wanted: in the wilderness without any chemical or preservatives.

To fulfill her dying wishes, Nate digs a hole in the woods and puts Lisa's body in it himself, which proves to be one of the most harrowing scenes in the series. Ultimately, though, it isn't clarified how Lisa met her end. Was she murdered? Did she commit suicide? These questions are never answered.

Gabe's Drug Addiction

Gabe is Claire's problematic boyfriend in the early seasons of the show. Viewers' first introduction to Claire and Gabe involves them smoking crack cocaine, and it only gets worse from there. It turns out Gabe, like all of the characters on the show, has a lot of unresolved trauma. After Gabe spreads rumors around school about his sexual relationship with Claire, she dumps him.

However, when Gabe's brother dies, Claire reaches out. It becomes clear Gabe's parents are abusive, and he soon falls deeper into drug addiction. Gabe's behavior becomes more erratic, and Claire eventually cuts ties with him for good, leaving audiences hanging in regards to Gabe's fate. Claire later envisions Gabe in the afterlife with his brother, Anthony, but this still doesn't give fans concrete evidence as to what happened to Claire's ex-boyfriend.

Maya And Willia's Relationship

After Lisa's death, Nate reunites with Brenda, and they try to create a family together. In the tragic final season of Six Feet Under, Nate dies due to complications with arteriovenous malformation, a brain condition. Brenda is pregnant when Nate passes, eventually giving birth to a girl named Willa.

RELATED: Which Family TV Drama Are You, Based On Your MBTI®

Even though the finale shows Willa and Maya together with Brenda and her new husband, many fans are still curious about how the relationship between Willa and Maya evolves. It also appears that Brenda is pregnant with another child. How do the siblings fare within their fractured, yet loving, family unit?

The Diaz Family Mortuary

Federico "Rico" Diaz is a restorative artist and embalmer who works for the Fishers. As the series progresses, he becomes more and more involved with the business, eventually buying 25% of Fisher & Sons. Rico often butts heads with David and Nate over the future of the business.

After Nate's death, "Rico" decides to divest from Fisher & Sons and purchase his own mortuary, which he renames Diaz Family Mortuary. The finale shows Rico prepping his sons to take over the business, which he eventually retires from. Do his sons take over? Do they follow in their father's morbid footsteps? It looks like we'll never know for sure.

Billy And Brenda's Relationship

Brenda has a very toxic relationship with her younger brother, Billy, played by Jeremy Sisto. Billy has severe mental health issues that require medication, yet he has a tendency to stop taking his medications because of how they affect him creatively. Billy is a photographer, and his struggles with mania both inform and undermine his work.

Even though their relationship is strained by Billy's poor boundaries, which culminates when he makes a sexual advance toward Brenda, they stay close. Billy is present when Brenda dies, leaving viewers to wonder just how they managed to remain in each other's lives without harming themselves or those around them.

Claire's Life Until 2025

Six Feet Under ends with Claire Fisher deciding to pack everything up and leave Los Angeles for New York City. Viewers don't see Claire again until she pops back up in the death montage circa 2025 when she's in her early 40s and moves back to Los Angeles.

RELATED: Six Feet Under: The 5 Best (& 5 Most Toxic) Relationships

What did Claire do when she lived in New York City? She's the last character to die in the ending montage, and her obituary indicates she became a photographer professor at NYU. What else did she do? Who else did she meet? Why did she eventually decide to move back to Los Angeles?

Keith's Sexuality

David's partner, Keith, is gay and proud, while David struggles in the early seasons of the show to share his sexuality with those around him, going as far as hiding his relationship with Keith from his family. Despite Keith's openness, viewers get hints that he may be sexually fluid when he becomes a bodyguard for a pop star named Celeste.

Celeste seduces Keith, and the pair have sex. The volatile pop star decides to fire Keith, who confesses what he did to David. While he is able to salvage his relationship with David, Keith's choice raises larger questions about his sexuality.

All The Visits From The Dead

The Fisher patriarch, Nathaniel Sr., haunts the dreams and fantasies of his kin throughout the series. The show does a fantastic job of delving into the trauma brought on by loss, and each episode attests to the pervasiveness of death, no matter how much people try to deny their own mortality.

RELATED: Where Are They Now: The Six Feet Under Cast

The show never quite resolves all the visions of the dead, and while this may drive some fans crazy, it's a testament to the unresolved nature of life. Six Feet Under has been hailed for its realistic characterizations, and its messy psychological underpinnings are brutally honest.

Sarah's Friendship With Bettina

Patricia Clarkson plays Ruth's younger sister, Sarah, who runs an artist's colony in Topanga Canyon. Kathy Bates plays Sarah's close friend, Bettina. Their relationship is strained when Sarah becomes addicted to Vicodin, a pain killer. Sarah lashes out at Bettina, who oversees her detox.

Eventually, Sarah goes to rehab, but the after-effects of her addiction to her relationship with Bettina are never explored. Bettina does develop a close relationship with Ruth, though.

The Political Differences Between Claire And Ted

Claire's love interest at the end of the series is a Republican lawyer named Ted who she meets while temping at a law office. They are very different. Ted is conservative and unartistic. Claire is liberal and oozing with creative energy. Somehow, though, they manage to carry on an intimate love affair.

Claire still decides to move to New York City, but when she returns in 2025, she reunites with Ted and the two marry, remaining together until the end of their lives. Considering how oppositional their views seem to be, audiences have a lot of questions about how they were able to maintain a stable partnership for so long.

NEXT: Six Feet Under: 10 Questions We Still Have 15 Years After The Series Ended