Euphoria to Game of Thrones, HBO already has plenty of impressive series under its belt, and even a couple of negatively received series have become water-cooler events.

With many exciting HBO shows still being developed, HBO continues to be the gold standard of network TV despite the network's name being dropped from Max. While there is a debate over which series was the best in HBO's history, popularity is a different discussion with different factors to consider. Taking into viewership, each show's impact on pop culture, how long they last before getting canceled or coming to a natural end, and spin-offs and movie sequels, these HBO series had the most people talking at the water cooler.

20 Watchmen (2019)

1 Season, 9 Episodes

Alan Moore's Watchmen remains possibly the most acclaimed and influential graphic novel of all time. Adapting it to Hollywood has proven difficult with Zack Snyder's attempt in 2009 earning mixed responses and a negative reaction from the author himself. HBO attempted something that was perhaps even bolder with their limited series Watchmen -- making a sequel story to the original graphic novel, commenting on the themes Moore first explored in a new era.

The series is a brilliant comment on racism, corruption, and heroism that will speak to any audience.

The series introduces plenty of new characters along with several returning characters from the original story with this alternate version of the United States in which masked vigilantism is outlawed and the police have taken an anonymous approach to fighting crime. The series is a brilliant comment on racism, corruption, and heroism that will speak to any audience. However, it is particularly thrilling for fans of the original story in how it builds on the mythology in such compelling ways.

19 Rome (2005-2007)

2 Seasons, 22 Episodes

It could be argued that there would be no Game of Thrones were it not for Rome. The epic, big-budget series was the network's first ambitious attempt at telling a story filled with battles and massive sets. While not the ratings success that Game of Thrones was, Rome represents a strong turning point in HBO's blockbuster storytelling. The series is set in Ancient Rome and follows two warriors who become entangled with some of the city's biggest moments, such as the fall of Julius Caesar and the arrival of Cleopatra.

Looking at Game of Thrones, the action is little in comparison, but the scale of the series is still impressive. However, the real thrill of the show comes down to the characters, with the relationships and political intrigue feeling like the best aspects of the early seasons of Game of Thrones.

18 The Leftovers (2014-2017)

3 Seasons, 28 Episodes

The Leftovers is an HBO series that had plenty of fans when it was on but was never one of the network's biggest successes. Similar to The Wire, now that the series is off the air, more and more people are discovering it as one of the greatest shows of all time. The Leftovers begins with the intriguing premise of the world suddenly losing a large number of its population as people suddenly disappear. The series then follows those left behind in an emptier world.

The series begins with a big and thrilling sci-fi concept but then makes an incredibly human and intimate story that deals with loss and grief in powerful ways. However, it is also an uplifting story of people finding love and happiness in a world filled with sadness. Unlike Lost, it is not about the mystery of where everyone went, but rather the drama of what the others will do now.

17 Deadwood (2004-2006)

3 Seasons, 36 Episodes

Deadwood was another glimpse of HBO getting bolder with their television storytelling, making an expensive Western story filled with colorful and brutal characters. Deadwood draws from historical aspects in the story of the various residents of the lawless town of Deadwood where many people, including Western icons, came seeking their fortune with the alleged gold to be found. At the center of the story are the noble yet short-tempted lawman Seth Bullock (Timothy Olyphant) and the nefarious bar owner and criminal boss Al Swearengen (Ian McShane).

The series is written by TV legend David Milch and his dialogue is the secret sauce that makes Deadwood so spectacular. Some have described it as "Shakespeare in the mud" with characters launching into captivating soliloquies and monologues filled with vulgarity and threats of violence. It also features a brilliant ensemble with McShane giving the commanding performance of the piece.

16 Veep (2012-2019)

7 Seasons, 65 Episodes

With former Vice President of the United States Kamala Harris' recent bid for the presidency, Veep returned to the cultural conversation with renewed praise for it as one of the best comedy series of the 21st century. Julia Louis-Dreyfus stars as Selina Meyer, who at the beginning of the series is the overlooked Vice President of the United States, constantly frustrated with her lack of power in the seemingly meaningless position. Surrounded by a staff of eccentric employees, she makes it her mission to become president at any cost.

From Armando Iannucci, Veep is a sharp and clever political satire that hilariously takes a look at the most self-serving and ego-filled aspects of modern politics. Louis-Dreyfus further solidified herself as one of the greatest comedic actors of all time with a performance that earned her six Emmys. She is surrounded by a cast of wonderful actors giving hilarious performances in a series that increasingly embraced the dark comedy of its world.

15 Big Little Lies (2017)

2 Seasons, 14 Episodes

Based on the Big Little Lies novel by Liane Moriarty, Big Little Lies is a must-see for several reasons, the foremost being its all-star cast featuring Reese Witherspoon, Nicole Kidman, Meryl Streep, and more. The Emmy-winning show tells the story of a group of upper-class mothers who end up banding together in the face of secrets and murder. Highlighting the competitive and cutthroat nature of the upper class, the show puts a spin on the seemingly perfect lives of the rich and successful.

The series manages to pull off a lot with its look at the class divide, the gripping mystery at the center, complex relationships, and some heavy subject matter. After two intense seasons, there is now confirmation that Big Little Lies season 3 is happening, bringing the audience back to this beautiful-looking community with darkness lurking under the surface.

14 Barry (2018-2023)

4 Seasons, 32 Episodes

Coming off of his time on Saturday Night Live, Bill Hader's series Barry delivered something that his fans likely weren't expecting as it is one of the boldest dark comedies in recent television. Hader plays Barry, a troubled ex-soldier and current hitman who travels to Los Angeles for a job and finds himself falling in love with the world of acting. While it might sound like a goofy fish-out-of-water story, Barry is much more than that.

The show has a typical HBO approach with its violence and drama with underlying dark comedy, and that is why it has become one of the most popular HBO shows of all time. Barry's final series has unfortunately followed suit just like many other HBO shows, as the Barry ending divided some critics. However, that's just a testament to how consistently great most of the show is, and it's so difficult to satisfyingly bring a beloved and supremely popular show to an end.

13 True Detective (2014-Present)

4 Seasons, 30 Episodes

True Detective season 1 is the first major example of A-list movie stars fully embracing the television medium, as Woody Harrelson and Matthew McConaughey play two detectives investigating a cold case. Each season that followed brought in a new case with a new set of A-list actors including the likes of Colin Farrell, Mahershala Ali, and Jodie Foster. While the cases were all intriguing, the show was always more focused on the characters who investigated them.

The inconsistent season releases have kept the series from achieving the level of popularity that crime dramas like The Sopranos reached. However, the long break between seasons means that the network and showrunners are prioritizing the series' quality, it is a series that continues to grab the attention of the audience, with the latest season 4 of True Detective becoming one of the most talked-about series of the year.

12 Westworld (2016-2022)

4 Seasons, 36 Episodes

It might seem surprising that a complex and challenging sci-fi series would come out of an adaptation of a mostly forgotten B-movie from the 70s, but Westworld surprised many people. The story is set in the future where one of the most popular attractions for high-paying tourists is a theme park styled on the Old West in which guests interact with an expansive world with robotic characters there to serve their every whim. However, this changes when the robots begin thinking for themselves.

Westworld is full of iconic scenes and features a great ensemble cast, starring Evan Rachel Wood, Thandiwe Newton, Jeffrey Wright, Anthony Hopkins, and many more throughout its three seasons. The popular show dives into a uniquely trippy and calculated dream world that is both futuristic and vintage, making it difficult for viewers to pinpoint what is coming next. The drama is action-packed as well as mysterious, which is partly why the show has a devoted following. Though Westworld's abrupt cancelation proved the show had fallen from favor, the first season of the show was an epic pop culture event.

11 Band Of Brothers (2001)

1 Season, 10 Episodes

Band of Brothers was a ground-breaking bit of television that showed the epic stories that could be told on the small screen, giving way to hugely ambitious shows to follow. This 10-part miniseries chronicled the journey of the soldiers of Easy Company from their days in basic training to the frontlines of World War II in Europe to the end of the war. Throughout the series, they achieve great victories, suffer devastating losses, and learn why they fight.

The Emmy-winning series not only offers a touching story about brotherhood, but it details the harrowing experiences on the battlefield as well with stunning war sequences unlike anything seen on television at the time. Based on Stephen E. Ambrose's novel of the same name, the show was hugely successful at the time of its release, but it has managed to hold onto its acclaim and popularity, which is a rare feat for a miniseries.