Ah, Friends. It's been nearly 20 years since the season finale of the show aired, and - for the most part - it still never gets old. Its technology, on the other hand...

It was way back in 1994 when the world was first introduced to Chandler, Joey, Ross, Rachel, Monica and Phoebe, and while a lot of their storylines might have aged well, there are a lot of other aspects of the show which give its age away.

NBC

From the fashion choices and hairstyles to the references and the complete absence of smartphones, Friends is truly a product of the '90s and early '00s, right down to the way that creators expected people to be watching.

A lot of people will remember the huge TVs that used to air the show - and I don't mean huge in terms of width. I'm talking chunky-backed, old-school screens that took up half the living room with a standard 4:3 aspect ratio.

These definitely weren't smart TVs, and Netflix was nothing but a whisper of a dream at that stage, so at the time creators apparently didn't have to worry too much about what was going on on the edge of the film, beyond that 4:3 ratio.

But maybe they should have.

NBC

In a post shared online, one fan of the show spotted a 'literal plot hole' in the show; one that probably wouldn't have been visible before the age of Netflix, when users are able to watch the show on their widescreen TVs with the wider aspect ratio of 16:9.

TikTok user Riley hit pause on the episode, which was the opening episode of Season 10, titled 'The One After Joey and Rachel Kiss'.

Don't @ me over spoilers, it's been nearly 20 years.

Anyway, in the episode we see Joey returning home to his apartment, closing the door we've seen so many times before. But on Riley's TV there's another detail visible, and it's pretty hard to miss.

"I love when you can tell something was shot with a camera that had no intention of ever being put on a widescreen TV," Riley said.

"I'm watching Friends, and look at this," she said, pointing to the right of Joey's door.

"Look at that giant hole in the side of Joey and Chandler's apartment!"

TikTok/@rileysoley

The video clearly showed a huge, square hole cut out of the wall of the set, presumably used to help position equipment as the crew filmed the inside of the apartment.

Some fans have questioned why the hole was even included in the frame in the first place, but if Riley's theory is correct, it's because the camera people probably assumed it would be cut off by the time it made it to TV.

Other TikTokers have apparently found other instances of the wider aspect ratio revealing funny details, with one writing: "They have so many! In one, Joey was supposed to be out of frame but you can see him covering his mouth laughing."

I suppose the crew couldn't have known just how big the picture was going to get in the future, but it's a good warning for anyone standing behind a camera!