1.) Before it aired, Friends went through several name changes – “Friends Like These,” “Six Of One,” “Across The Hall,” “Friends Like Us,” & “Insomnia Cafe” until they settled on “Friends.”
2.) Gunther, who is played by James Michael Tyler, was extra in the first season. He earned his re-occurring role in Friends because he was the only one who could work the cappuccino machine.
3.) In the episode where Phoebe, Monica, and Rachel were on the balcony, Rachel knocks the pillow over the edge – that wasn’t even supposed to happen. They just ran with it after it fell off.
4.) Giovanni Ribisi (who also plays Frank Jr, Phoebe’s brother) played the extra who walked by and dropped the condom in Phoebe’s guitar case when she is playing outside.
5.) In 2006 a cafe in Dubai named “Central Perk” was opened & as a PR stunt, they had James Michael Tyler (Gunther) open it.
6.) In the episode where Phoebe is pretending to come on to Chandler to expose his relationship with Monica – one of the reasons, the audience laughed so much when he opened her blouse in one swift move and proclaimed, “it is not my first time” was because it took 12 attempts to get it open in filming.
7.) The frame on Monica’s door surrounding the peephole was originally a mirror – but a crew member smashed it by accident.
8.) While filming Friends, David Schwimmer was offered Will Smith’s part in “Men in Black” but turned it down.
9.) Reese Witherspoon was signed up for six episodes of friends, but apparently (unconfirmed) Jennifer Aniston disliked her and asked the producers to fire her.
10.) Originally Matthew Perry (Chandler) was offered the role in “Lost in Space.” He declined and tipped the casting people about Matthew LeBlanc, which is how Matt got the part.