Sadly The Big Bang Theory ended earlier this year after 12 seasons, leaving loyal fans with a gaping hole in their hearts - despite the "perfect" finale.
As such, many have chosen to rewatch the hit sitcom, which starred Jim Parsons, Johny Galecki and Kaley Cuoco.
This rewatch has caused some to notice a rather glaring issue with the show's timeline and become confused about when Leonard and Sheldon actually first met.
Many will recall that in the season three episode The Staircase Implementation, Leonard (Galecki) tells Penny (Cuoco) about his first time meeting Sheldon (Parsons), which he claims was in 2003.
He explains how he knocked on Sheldon's door back in 2003 to check out the spare room for rent that he'd seen advertised.
But before being allowed into the apartment, he first had to pass Sheldon's unusual test, answering which Star Trek character is better - Picard or Kirk.
Leonard 'correctly' says Picard and adds that the original series was better than "Star Trek Next Generation".
And that was that, Leonard got the room and the pair became unlikely friends.
Or so we thought....
However, in a later episode of the show, the date the pair met is called into question.
As a clued-up Reddit user points out, in The 21 Second Excitation from season four, Sheldon reminisces about the time he and Leonard queued for 14 hours to attend the Star Trek: Nemesis premiere.
But that simply couldn't have been possible as that movie was released in America in 2002 - months before Leonard and Sheldon were supposed to have met.
Fellow fans on Reddit were surprised to discover the blunder - with some saying they were going to just ignore it.
One commented: "I’m just going to imagine that they did queue up for the premiere in 2002 together, but only by coincidence, and they met properly a year later when Leonard needed a place to stay. I know that isn’t possible either but it’s what I’m going with."
Someone else replied: "I'm guessing it's a plot hole."
A third pointed out a different mistake they'd seen, writing: "A small mistake I see recently when I started watching season one again, in episode three.
"Leonard came home with a scratching post. Leonard said to Sheldon 'I know what you're thinking, I've taken your asthma into account.' But in the later season we see that it's Leonard and not Sheldon that has asthma."
