Glaring continuity errors from 25 popular TV series

"Stranger Things" creators Matt and Ross Duffer got a rude awakening during Season 4 when the popular sci-fi Netflix series' legion of fans took to social media to air their grievances about a major plot hole.

Early on, the series establishes Will Byers' birthday as March 22, but in Season 4, a time stamp shows the date as March 22 while Will and his friends are on a roller-skating trip, with no mention of his birthday. Did his friends forget? Nope, but the writers and creators did. The Duffer Brothers plan to retcon it by changing the Season 2 episode in which Will's mom, Joyce (Winona Ryder), first mentions the date. "We're thinking his new birthday … is going to be May 22nd, because 'May' can fit in Winona's mouth," Matt told Variety.

The character of Miley Stewart didn't have the easiest time balancing her secret double life as a typical teenager and pop phenomenon Hannah Montana on the eponymous Disney Channel series—and, as it turns out, the writers didn't have the easiest time balancing the narrative consistencies either.

In 2020, nine years after the series ended, fan Kylie Klunder took to TikTok to call out the show for revealing the identity of Miley/Hannah's famous country music star father, Robby Ray Stewart (played by Miley Cyrus's real-life dad, country singer Billy Ray Cyrus), across multiple episodes. Miley and Robby casually refer to themselves as father and daughter to people, whether Miley is Miley or Hannah Montana. Miley has a secret identity, but Robby Ray doesn't: "And nobody ever put it together!" Klunder bemoans.

In the afterlife depicted in "The Good Place," Chidi (William Jackson Harper) speaks American-accented English despite revealing to Eleanor (Kristen Bell) that his first language, while alive, was French. The sitcom explains this as the result of the magical nature of the afterlife, but later on, Chidi speaks English with an American accent back on Earth.

In an interview with Rolling Stone, series creator Mike Schur revealed he "accounted for Chidi's speaking English as a sort of show cheat—we did consider subtitled French, but comedy requires timing and pace and rhythm, and subtitles are bad for that." Schur also felt the switch to English could be confusing, but "because we're continuity/backstory nerds, we give the audience an explanation for his accent/non-accent very early in the [third] season."

Every fan knows the origin stories of how the six main characters met on "Friends," right? Well, the show's writers seemed confused when it came to Rachel (Jennifer Aniston) and Chandler (Matthew Perry) since they ended up giving the characters' friendship multiple origin stories.

In the pilot episode, Rachel runs from her wedding to Central Perk, where her old high school best friend Monica (Courteney Cox) introduces her to Chandler, Phoebe (Lisa Kudrow), and Joey (Matt LeBlanc), seemingly for the first time. Yet in Season 3's "The One With The Flashback" and the Season 5 flashback episode "The One With All The Thanksgivings," there's an entirely different story presented of how Rachel and Chandler's first met, going back much further than the events of the series pilot.

In those episodes, Ross (David Schwimmer) brings his college friend Chandler home for Thanksgiving, where he meets Monica and Rachel. Then, even more egregious, in Season 10's "The One Where the Stripper Cries," it's revealed that Chandler and Rachel kissed at a college party.

Shootouts and chase scenes were common on "Sons of Anarchy," which aired between 2008 and 2014, but that didn't mean the chase scenes were always consistent. One chase scene in Season 5, Episode 11 features the astonishing case of a seemingly self-repairing car.

When things get too heated between the SAMCRO motorcycle crew and a rival Mexican gang during a violent confrontation, they flee in a station wagon that becomes destroyed after hitting a gate—a couple of seconds later, that same car is right as rain.

Before "The Big Bang Theory," Johnny Galecki starred as David Healy on "Roseanne," the love interest and eventual husband of Darlene Conner (Sara Gilbert). His first appearance came in the Season 4 episode "The Bowling Show," however, David introduces himself to the Conner family as Kevin, not David.

The show attempts to retcon this apparent error in a Season 6 episode, "Everyone Comes to Jackie's," by having Roseanne explain that Darlene made up the name David because she has so much influence over him. Darlene's mom Roseanne (Roseanne Barr), says, "David isn't even his real name—she just made that up!"

Before Frasier Crane (Kelsey Grammer) got his eponymous spinoff series, he was a supporting character on the iconic '80s sitcom "Cheers." In the original series, in Season 8, Episode 9, "Two Girls for Every Boyd," Frasier remarks that his late father was a scientist.

Cut to the '90s spinoff "Frasier," where his dad is alive and well—and a former cop—named Martin Crane (John Mahoney). In a Season 2 episode of "Frasier," a crossover appearance from Sam Malone, Ted Danson's character from "Cheers," allowed Frasier to explain that he was simply estranged from his father at the time and lied about him being dead.

A recurring joke throughout the 12 seasons of "The Big Bang Theory" is the perpetually broken elevator in the main characters' apartment building. In the series' first season, in 2008, the guys buy a time machine and are forced to carry it up the stairs, with Leonard (Johnny Galecki) explaining to Howard (Simon Helberg) the elevator has been broken for the past two years, which would be 2006.

But in the Season 3 episode "The Staircase Implementation," the reasoning for the broken elevator is revealed, with the timeline going back to 2003, an additional three years earlier than the initial timeline—one of a few plot holes that stirred fans.

Fans of "Supernatural" stuck around with the long-running show for a whopping 15 years, but such an impressive tenure increases the chances the series would goof up here and there. But fans noticed some pretty glaring ones right from the jump in Season 1.

In the first season episode "Provenance," Dean (Jensen Ackles) calls his brother Sam "Jared" at one point, which is the name of the actor who plays Sam, Jared Padalecki. In another scene, an extra appears to call Dean "Jensen."

George Clooney's career kicked off after starring as Dr. Doug Ross in the medical drama "E.R." The beloved character was also central to one of the series' most confounding plot holes. In Season 1, Ross reveals to a nurse that he had a son before the twin daughters he eventually has with nurse manager Carol Hathaway (Julianna Margulies). Later in the show, he tells another nurse that he's never met the son, nor does he know his name.

Ultimately, no one ever mentions the child again. While seemingly an abandoned plot point, "E.R." executive producer John Wells explained it away to TVLine in 2019 by simply saying, "There are people among us who lose track of their children."

J.D. (Zach Braff) and Turk (Donald Faison) had one of the most beloved bromances in television history on "Scrubs," but there are conflicting accounts about the origins of that friendship. In Season 2's "My Kingdom," viewers are treated to flashbacks of J.D. and Turk in college, including how they met when J.D. arrived at their dorm room and introduced himself to his future best friend.

Yet in the Season 4 episode "My Changing Ways," another flashback to that same time in college shows J.D. as the one who arrived at the dorm for the first. Turk walks into the room to see J.D. wearing a wizard hat in front of his computer.

It's challenging to keep track of all the vampire lore on a show like "Buffy the Vampire Slayer," so it's not a big surprise the series occasionally contradicted itself.

In Season 1, when Angel (David Boreanaz) cannot perform CPR, we learn that vampires don't breathe—you know, what with being dead and all. But that idea is constantly contradicted by the fact that the vampires talk during the show, occasionally smoke cigarettes, and are even strangled. If they couldn't breathe, how would strangling them be effective? Fans wondered the same thing.

Many "Game of Thrones" fans felt the hit HBO series got a little sloppy toward the end, and the most infamous (or at least viral) continuity error that came up in the show's final season only bolstered those feelings.

In Season 9, Episode 4, eagle-eyed viewers spotted a disposable Starbucks cup on the table in front of Daenerys (Emilia Clarke). Was the series simply getting more modern as it came to a close? Nope, it was a genuine mistake, as the show's executive producer Bernie Caulfield admitted in a 2019 interview.

Even prestige historical dramas are not free from the pitfalls of missed continuity gaffes. One major inconsistency occurred in History Channel's "Vikings" in the second season.

When the character Ragnar Lothbrok (Travis Fimmel) leaves for a raid in Episode 2, he speaks to his unborn child, named Sigurd, through his wife's stomach. When Ragnar returns in Episode 4 and discovers the child has arrived, he asks what the name is.

In the case of a show as convoluted as "Riverdale," you may expect some plot holes because there's a level of suspension of disbelief when dealing with matters like murders, milkshakes, gangs, and Gargoyle Kings.

One of many inconsistencies involves the ages of twins Cheryl and Jason Blossom (Madelaine Petsch and Trevor Stines). The series starts with the mysterious death of Jason, seen throughout the series in flashbacks. Being twins, Cheryl and Jason are supposed to be the same age. However, Cheryl is in the same grade as Betty Cooper (Lili Reinhart), but Jason appears in the same class as Polly Cooper (Tiera Skovbye), Betty's older sister.

The first episode of the cop comedy "Brooklyn Nine-Nine" sees Terry Jeffords (Terry Crews) give the newly instated Captain Holt (Andre Braugher) quick introductions of the detectives in his unit. Terry points out three of the lazier detectives in the precinct: Scully, Hitchcock, and Daniels.

While Daniels is never seen, mentioned, or heard from again, Scully (Joel McKinnon Miller) and Hitchcock (Dirk Blocker) go on to be central characters. Seemingly the writers changed their minds about the Daniels. Nevertheless, fans have wondered about what happened to her.

It can be a challenge for a series to maintain chronology when set in the past, and there's no better example of that than the Christmas-themed episodes of "That '70s Show." The series lasted eight seasons while taking place over four years, but there are five Christmas episodes throughout the show's run.

How were there five Christmases in only four years, you ask? That's that magic of TV for you.

Like the age-old question regarding chickens and eggs, a similar one exists for "The Office": Who came to Dunder Mifflin first—Jim (John Krasinski) or Pam (Jenna Fischer)? It's a question the show addressed twice, but with two different answers.

In the Season 2 episode "The Secret," Jim tells Pam he had a crush on her when she first started, which would imply he was at the company first; then, in Season 4's "The Launch Party," Jim asks Pam what she said to him on his first day of work.

In the Season 6 episode of "The Simpsons," "And Maggie Makes Three," baby Maggie Simpson's origin story is revealed in a flashback. There's a pretty glaring blunder in the background of one scene, in which a pregnant Marge talks to Homer in their living room, where a framed photo of not-yet-born Maggie is on the wall behind them.

It's a mistake that went unnoticed until over two decades after the 1995 episode aired, when "Simpsons" executive producer Matt Selman spotted it and posted it on Twitter in 2018, with writer Al Jean backing him up.

In the Season 1 episode of "Gilmore Girls" titled "Kiss and Tell," the lovelorn protagonist Rory Gilmore (Alexis Bledel) learns a few things about her new crush, Dean Forester (Jared Padalecki), courtesy of her friend Lane (Keiko Agena).

One of those revelations is that Dean is allergic to walnuts—not just mildly allergic, but deathly allergic. So, it's concerning that in the very next episode, Rory delivers a batch of rocky road cookies (which traditionally contain walnuts) to Dean, who even responds to her gift with bewildering delight. Perhaps she substituted the nut?

A show as long-running as "Grey's Anatomy" is bound to have a good amount of continuity issues—and an enormous fan base that's guaranteed to notice them. Take, for example, the Season 7 episode "That's Me Trying," in which Dr. Owen Hunt (Kevin McKidd) puts the doctors through a series of trauma certification drills.

In one exercise, they are drenched with water to test their focus. The showrunners seemed to overlook just how long the characters should remain wet-looking, as Alex Karev (Justin Chambers) is too suddenly dry.

In the historical time-travel series "Outlander," Claire (Caitríona Balfe), a WWII military nurse based in Scotland, becomes transported back in time to the 18th century, where she unexpectedly falls in love with a Highland warrior named Jamie Fraser (Sam Heughan).

In Season 1, Episode 7, Claire says she cannot marry Jamie to officially become a Scot because she doesn't know his real name. Yet fans called out that in the previous episode, Claire reads over the marriage contract, which shows both parties' full names.

Before Will's birthday got mixed up on "Stranger Things," Pacey Witter (Joshua Jackson) suffered the same fate on the early aughts show "Dawson's Creek." The series chronicles the tumultuous journey of adolescence, and as most people know, teenagers love an excuse to throw a party.

In the Season 4 episode "The Te of Pacey," Pacey's friends throw him a surprise shindig, and throughout the episode, the characters wear hats and winter coats. Yet previously, in the Season 2 episode "The Crossroads," Pacey turns 16 in the summertime before school starts. Maybe it was a half-birthday celebration?

Problematic mother Betty Draper (January Jones) is one of the most compelling characters on AMC's "Mad Men," partly thanks to the bizarre relationship she cultivates with the next-door neighbor's odd-duck son, Glen (Marten Holden Weiner).

In Season 2, Episode 10, "The Inheritance," Betty sits with Glen on her living room couch to watch cartoons while holding a Coca-Cola with a red straw. That straw disappears and reappears from shot to shot.

"Peaky Blinders" thrilled fans for six seasons, chronicling the titular crime gang loosely based on a real urban British youth gang in the late 19th and early 20th centuries. Costuming is key for period pieces like this—but unfortunately, a costuming-related gaffe slipped by in the editing room in the Season 3 premiere.

When Arthur Shelby (Paul Anderson) leaves to see his brother, Tommy (Cillian Murphy), he places his coat on the chair behind him. Yet, when he arrives at Tommy's doorstep, the coat is miraculously wrapped around him again.

Story editing by Jaimie Etkin. Copy editing by Kristen Wegrzyn. Photo selection by Clarese Moller.