It’s unclear when Barney Stinson learned how to drive.
On season two, episode 17, “Arrivederci, Fiero,” Barney needs a ride to his massage appointment in Queens, but Marshall isn’t available to take him. Ted suggests he just take Marshall’s car, but Barney visibly balks at the idea.
After some prodding, Barney reveals he never learned how to drive, so Ted offers to teach him. But the lesson doesn’t go well as Barney is terrified and unable to go past 2 miles per hour.
Yet just one episode later, “Moving Day,” Barney is somehow able to steal Ted’s moving truck.
Later, on season four, Barney also said he once drove Ted’s mom to the airport, and on season five, episode 24, “Doppelgangers,” Barney admits to driving a cab to pick up women.
But it’s never explained how or when Barney got over his fear of driving and got a license.
There are conflicting dates for the St. Patrick’s Day incident of 2008.
On season three, episode 12, “No Tomorrow,” the central friend group decides to split up to celebrate St. Patrick’s Day.
Lily, Marshall, Robin, and Ted gather for a board-game night at Lily and Marshall’s new apartment, but Barney goes all out for a night on the town in a green suit.
Barney eventually persuades Ted to join him at the party after he secures him a date, and the night ends up taking some wild turns.
Later in the episode, we find out that Ted’s future wife, Tracy, was also at the same party.
When Ted returns to the club the next morning to look for his phone, he ends up taking an abandoned yellow umbrella — a recurring prop that connects Ted and Tracy together before they officially meet — to shelter himself from a sudden storm.
But when Tracy recalls the night years later, the date doesn’t coincide. In her version, it happened in April 2008, but on season three it went down on March 17th, 2008.
Co-showrunner Carter Bays responded to fan questions about the inconsistency in 2014.
He tweeted, “Pretty sure that in 2008 St. Patty’s Day was in April. Yeah I’m right about this. Don’t look it up. I’m right. (CASUALLY BACKS OUT THE DOOR).”
The pineapple incident is one of the series’ biggest mysteries.
On season one, episode 10, “The Pineapple Incident,” Barney, Marshall, and Lily convince Ted to be a little more spontaneous — which leads to him taking five shots of bartender Carl’s “Red Dragon” and blacking out.
When he wakes up the next morning, there’s a woman he doesn’t know in his bed and a pineapple on his nightstand. He also has a sprained ankle, and his coat is singed.
Throughout the episode, Ted tries to piece together the events of the night before by asking his friends what he did.
He eventually finds answers for the woman in his bed, Trudy, the sprained ankle, and the burn mark on his coat, but the pineapple remained a mystery.
A deleted scene called “The Complete Story” on the full-series DVD collection released in 2014 finally explained how Ted got the pineapple, but it was never solved on the actual series.
Robin is a self-acclaimed gun aficionado, but she’s afraid of Not-Moby’s gun on season one.
Throughout the series, fans find out that tough-as-nails Canadian Robin carries a gun in her purse, wears a gun-shaped pendant, subscribes to a guns-and-ammunition publication, and visits the shooting range when she needs to work through emotions.
Yet, on season one, episode 11, “The Limo,” she is terrified when Not-Moby (a guy who they thought was recording artist Moby) brandishes a gun as the friends are hopping between New Year’s Eve parties.
The most likely explanation is that the writers hadn’t fully fleshed out Robin’s character that early on in the series, but now it’s become a pretty blatant character inconsistency.
Robin says Lily can’t live with her because she’s allergic to her dogs, but they never seem to be a problem.
After moving back to New York from San Francisco on season two, Lily moves into a tiny run-down apartment that’s barely inhabitable.
When Ted and Robin visit her, they try to come up with a solution. But Lily can’t move in with Ted because of her ugly breakup with Marshall, and she can’t move in with Robin because she’s allergic to her many dogs.
But a few episodes prior, Lily was hanging out at Robin’s place and coexisting with the dogs quite well. She even sits on Robin’s couch and pets one of the furry friends on the very next episode, “Aldrin Justice.”
Either Robin lied about Lily’s allergies to avoid having her move in with her, or her allergies are easily controllable.
All of Robin’s female friends seem to disappear.
Throughout the series, Robin is framed as the ultimate “guy’s girl.”
Though she and Lily eventually become besties, on season nine, episode four, “The Broken Code,” Lily struggles to plan Robin’s bachelorette party because she says she has no female friends.
But when we were first introduced to Robin on the pilot episode, she was surrounded by a group of women at the bar. And we see her hanging out with other girlfriends on various episodes throughout the series.
It’s unclear whether Marshall knows how to fight.
Lily calls Marshall her “marshmallow” because he’s a big softie.
He proves this on season one, episode three, “The Sweet Taste of Liberty,” when he’s relieved that he doesn’t have to fight a man who he mistakenly thought was hitting on his “Lily pad.”
On that episode, he even says he’s never been in a fight before.
But on season four, episode 10, “The Fight,” Marshall contradicts this.
It turns out that he’d been in plenty of nasty fights growing up with his brothers in Minnesota, and he was easily able to take down a bartender who punched Ted.
A windshield breaks and is magically repaired in the blink of an eye on season two.
On season two, episode seven, “Swarley,” Barney and Ted try to explain their theory about women with “crazy eyes” to Marshall by giving personal accounts of disastrous dates.
Ted tells the tale of his brief liaison with a woman named Janine who had a bit of an anger-management issue.
In the flashback scene, we see Janine smashing the windshield of a car that almost bumped into them. But in the next shot, barely a second later, the windshield is as good as new.
Barney says he dated Wendy the waitress, but their earlier interactions say otherwise.
Barney dated his fair share of women on the show, but it was still somewhat surprising on season three when he claimed he was in a relationship with Wendy, the waitress from MacLaren’s Pub, in 2005.
Season one took place in 2005, so it seems unlikely that they would’ve been able to keep their relationship a secret considering how much time the friends spend at the bar.
And, on season two, episode three, “Brunch,” Barney openly flirts with Wendy without giving any indication that he knew her — let alone dated her — previously.
None of Marshall or Lily’s relatives seemed to be at their wedding.
Marshall and Lily’s wedding was a sweet, two-part season-two finale that many fans looked forward to. But it seems like none of their immediate family members got an invite.
We later learn that Lily is estranged from her father, which explains his absence.
But Marshall’s close-knit family was introduced back on season one, episode nine, “Belly Full of Turkey,” so it’s odd that none of them are shown at the wedding.
Marshall and Lily didn’t always share a toothbrush when they lived with Ted.
On season five, episode 14, “The Perfect Week,” Marshall and Lily say that they’ve shared a toothbrush for years — and Ted comes to the unfortunate conclusion that he’d also been sharing it with them when they lived together.
However, on season one, episode 14, “Zip Zip Zip,” when Marshall and Lily are trapped in the bathroom together while Ted romances Victoria, they are clearly shown using two, separate toothbrushes.
Robin claims to have never played team sports, but she also said she missed her prom for a field-hockey game.
On season one, episode six, “The Slutty Pumpkin,” Robin says she only played tennis — never team sports — as a kid.
But toward the end of season one, on “Best Prom Ever,” she shares that she missed her high-school prom because she had a field-hockey game.
Barney breaks one of his cardinal suit rules at Mr. Eriksen’s funeral.
Barney’s love affair with suits is a recurring character trait throughout the series, and there are several times he reveals his rules about when he does and doesn’t “suit up.”
On season two, episode 14, “Monday Night Football,” Barney shares that he’d never wear a suit to a funeral because suits should only be worn at happy events.
And yet, at Marshall’s dad’s funeral on season six, Barney dons a classic black suit.
Barney’s brother-in-law is played by two different actors throughout the series.
On season two, episode 10, “Single Stamina,” Barney finds out that his brother, James, is engaged to a man named Tom.
As Barney is lamenting the loss of his greatest wingman, James shows him a picture of Tom on his phone.
But when Tom is formally introduced on season seven, episode 11, “The Rebound Girl,” he’s played by a totally different actor than the man in the picture.
Gary Blauman apparently rose from the dead.
Gary Blauman was introduced on season one, episode 17, “Life Among the Gorillas,” as one of Marshall and Barney’s coworkers.
On season three, episode 15, “The Chain of Screaming,” Barney tried to teach Marshall a lesson with one of his fanciful stories about how after Gary yelled at his boss, he went down a path where he eventually quit, became a janitor, and died.
But he reappears on season four, episode 16, “Sorry, Bro,” and he’s still working at Goliath National Bank.
He returns on a few later episodes as well, including season nine, episode 21, “Gary Blauman,” when he shows up at Barney and Robin’s wedding.
All things considered, Barney most likely just lied about Gary’s death in an effort to prove his point.
There’s a bit of confusion surrounding Barney and Robin’s wedding date.
On season eight, episode 13, “Band or DJ?” Ted offers to help plan Robin and Barney’s wedding, and he explicitly states that the ceremony will take place on May 25, 2013 — which was a Saturday.
But season nine opens with a title card reading “Friday 11 a.m. 55 hours before the wedding.” Making the wedding day Sunday, May 26.
We see the entire wedding weekend play out on the final season, so it’s clear that the season-eight date was incorrect.