Continuity mistake: In 2-21 Something Borrowed, Lily's high school boyfriend, Scooter, reveals his name is Bill, but this episode in a flashback he tells Lily his name is Jeff. (00:03:47)
Other mistake: In the credits, Jeremy Gabriel (Robin's new 'boyfriend') is shown as "Mark" but it is "Mike" throughout the episode.
Other mistake: At the beginning of the series, Ted starts telling the story of how he met the mother of their children. When he starts describing how he met Robin, he doesn't reveal that it was not their mother until the end of the pilot. But children should have realised it wasn't their mother when Robin said she was a journalist and worked as a TV presenter. The kids knew their mom wasn't a journalist, so they shouldn't have been surprised at the end of the episode when Ted said "this is how I met your aunt Robin".
Continuity mistake: When breaking up with Natalie, her hands are constantly changing position between instant cuts. (00:18:30)
Continuity mistake: When Ted mentions having a party, Marshall's hand goes from on his beer to on his chin instantly. (00:03:10)
Continuity mistake: In the pilot episode we see the Son and Daughter listening to the start of the story on how Ted met their mother. In the final episode of the show it's revealed that the whole story has taken place in one sitting. However, the clothes the kids are wearing and the items around them are different in the pilot episode to every other episode. The sofa is a different design, the cushions appear etc. (00:00:45)
Okay Awesome - S1-E5
Continuity mistake: Ted asks if he had a stroke at the start of the episode and puts his hand to his chest. Camera cuts and his hand has swapped from his right to his left on his chest. (00:00:35)
Continuity mistake: Barney tells Lily that she's rubbing his leg. When he does, a wine glass suddenly appears in Lily's hand. (00:03:20)
Sweet Taste of Liberty - S1-E3
Revealing mistake: Barney tells the cab driver to lock the doors, and he does. We then see Ted trying to open the door and you can hear the taxi is still driving by the engine noise. However, the scenery outside the windows has stopped moving. (00:01:50)
Continuity mistake: When Barney is scoping the apartment, his hands are next to his temples. As the shot changes to a wider shot, they are now much further away from his temple. (00:08:05)
Continuity mistake: When Barney is explaining about there always being 1 girl who doesn't know who's party it is, his hand is sudden;y outstretched or by his side depending on the shot. (00:08:00)
The Best Burger in New York - S4-E2
Continuity mistake: When Ted picks up his burger it already has a bite taken out of it, then in the next shot the burger is whole again. (00:20:09)
Continuity mistake: After telling the joke about the Teenage Mutant Ninja Turtles, Marshall's hands change between shots, from holding his hand for a hi-five to his pockets to holding the Skittles. (00:08:32)
Character mistake: In another episode it is revealed that Robin hates nicknames and reacts badly when she, or anyone else, is given a nickname. However, in this episode her and Marshall give each other nicknames, and she doesn't seem bothered at all.
Continuity mistake: When they are watching the music video on the small screen on the table, there is a bottle of JT Cola next to the screen in the close ups. When it goes to a wide shot, it is suddenly replaced by a beer bottle. However, in the previous shot before the commercial break it is a JT Cola bottle in the same spot as the beer bottle.
