Ah we do still love a good 'Friends' blooper. The show may now be analysed from the distance of 2019, and let's face it, hasn't aged well in some ways, but it's still watched and re-watched to this day.
This time around, it's a cameraman who shows up in season three's 'The One Without the Ski Trip'.
It's just after Ross and Rachel's break up so tensions are running high. You can watch the scene below, the cameraman shows up around the 1.50 mark.
In case you are wondering why you might have missed this first time around, it's down to the fact that 'Friends' was filmed in the '90s when TV shows were shot in the standard 4:3. aspect ratio.
If you are now watching the show on Netflix, you will be viewing it the wider aspect ratio of 16:9, which has become the norm. So the producers weren't just incredibly bad at their job, they just never thought you were going to see Todd the cameraman on screen. Still funny when we do though.