For twelve years, It's Always Sunny in Philadelphia has portrayed a group of narcissistic, delusional friends, nicknamed "The Gang," who run a bar called Paddy's Pub. On Netflix, Always Sunny is categorized as a cult TV show because of its passionate fanbase. However, there are many facts that go unnoticed by the shows regular audience. Here is a list of little-known facts about It's Always Sunny in Philadelphia:

1. Charlie’s Tattoo

In “Dennis and Dee Get a New Dad," Charlie is seen tattooing “Badnews” onto his forearm. However, he is interrupted by Frank and stops at “Badnew.” This tattoo has appeared on Charlie’s arm for every episode afterwards.

2. Filming Locations

Rob McElhenny, who plays Mac, is the creator of Always Sunny. McElhenny was raised in Philadelphia. In order to give the show a more authentic vibe, he arranged for it to be shot in L.A. and Philly. Mac’s mom’s house is actually located next-door to McElhenny’s childhood home.

3. RCG Productions

McElhenny, Charlie Day (Charlie), and Glenn Howerton (Dennis), own a production company called RCG, which stands for Rob, Charlie, and Glenn.

They are executive producers of Always Sunny and Unsupervised, which aired in 2012.

4. Hidden Messages

RCG decided to add hidden messages at the end of each episode. They are recorded backwards, and switch after every season.

Season one’s message is “You’re stupid for playing this forward.”

You can listen to the hidden messages here.

5. Nicki Potnick

In the first ten minutes of S1EP3, “Underage Drinking: A National Concern”, the gang reminisces about crashing former high school classmate Nikki Potnick’s car while drunk driving.

Nikki Potnick is mentioned again six seasons later, during “The High School Reunion.” Frank steals Nikki’s name tag and sneaks into the reunion to be with the gang. Nikki Potnick never appears on screen.

A theory spread around the Always Sunny fanbase that Nikki Potnick is The Waitress’s real name. Howerton denied this theory.

6. Every main cast members' spouse has appeared on the show.

Most Always Sunny fans know about the two married couples on set, Kaitlin Olson (Dee) and Mcelhenny, as well as Day and Mary Elizabeth Ellis (The Waitress.)

Howerton’s wife, Jill Latiano, has guest starred on the show. In “The D.E.N.N.I.S System”, Dennis explains the crazy cycle he uses to get women to fall for him. Latiano plays one of the poor women who falls for his trap.

DeVito’s wife, Rhea Perlman, appears in the live audience edition of “The Nightman Cometh.” His daughter, Lucy, has appeared in “The Gang Finds a Dumpster Baby," “Dennis and Dee Get a New Dad," and “Mac Bangs Dennis’ Mom.”

7. “The Gang Tries Desperately to Win an Award” is a metaphor for Always Sunny’s lack of Emmy nominations.

This episode features the gang going to extreme measures to win a "best bar" award. Hints about the metaphor are sprinkled throughout the episode.

Always Sunny wasn’t nominated for an Emmy until 2013, when Marc Scizak, who works as a stunt coordinator on the show, was nominated for his work. He was nominated again in 2014 and 2015, but never won.

8. McElhenny and Olson actually own a bar in Philadelphia.

The couple owns a gastropub named Mac’s Tavern, which is located on Market Street in Philadephia. The menu features “Mac’s Chili” and “Sweet Dee’s Turkey BLT.”

9. It’s Always Sunny in Philadelphia was originally titled It’s Always Sunny on TV.

The show was supposed to be about a group of friends who were struggling to make it as actors in Hollywood.

Fans theorize that this is why Dee’s pipe dream is to become an actress.

RCG also considered naming the show Jerks.

10. Rickety Cricket provides more to Always Sunny than being a hopeless street rat.

David Hornsby, who plays Rickety Cricket, the ex-priest turned homeless drug addict, is a producer on the show. He has also written and co-written thirty episodes, such as “Mac Kills His Dad," “The Gang Gets Quarantined," and “The Gang Runs For Office.”

11. Kristen Wiig was seriously considered for the role of Dee Reynolds.

During casting, McElhenny favored Wiig, because Olson skipped a significant line during her audition. Howerton convinced him that Olson was perfect for the part. McElhenny quickly fell in love with Olson, and they were married by 2008.

You can see Olson’s audition here.

12. Dee was originally written as a voice of reason.

During the early stages of writing, McElhenny admitted that he didn’t know how to make a female character “funny.” Olson replied, “Well, don’t write for a woman. Just write another funny character and I’ll make it a woman.”

Hence, Olson became one of the funniest and raunchiest women on television.

13. The McPoyles’s are based off real people.

McElhenny grew up in the same area as a very large family. People often joked about the family being incestuous because of how many siblings they had.

McElhenny was inspired by this, and wrote Liam, Ryan, and Margaret McPoyle as background characters.

Thankfully, the real McPoyle’s don’t practice incest.

14. Margaret McPoyle is actually beautiful.

Thesy Surface, who plays Margaret Mcpoyle, undergoes intense makeup before she films her scenes. In reality, she is nothing like the sweaty, unibrow-clad antagonist we see on screen.

Margaret never speaks a word, and was meant to only be in one episode. The casting department loved the way Surface portrayed Margaret's creepy demeanor, and kept her as a recurring cast member.

15. Howerton filmed the opening credits.

The Always Sunny theme song is accompanied by shaky camera footage of some of Philadelphia’s most well-known landmarks.

Knowing they had a low budget, RCG filmed the opening shots by themselves. They drove around Philly while Howerton filmed outside his window. The only thing they had to pay for during this shooting was gas.

16. The pilot was shot for under $100.

In 2004, RCG were all struggling actors. None of them could afford to hire a full crew, so the majority of the pilot was filmed in their separate apartments without professional help.

Originally, the pilot was supposed to be “Charlie Has Cancer," where Charlie pretends to have cancer so he can manipulate the gang.

RCG began looking for a station to air their program, and found support in FX president John Landgraf. Landgraf paid them to film a proper pilot and advised them to change the setting to Philadelphia.

They decided to write a different script for the pilot, and “Charlie Has Cancer” was moved to the fourth episode of the first season.

You can watch part of the original pilot here.

17. McElhenny was raised by two women, which is why Mac is gay.

Since season one, it has been a running joke that Mac is secretly gay. However, he represses his feelings because they contradict with his religious beliefs. He finally comes out in S12EP6, “Hero or Hate Crime?”

McElhenny has a strong passion for LGBT rights, because he was raised by a gay couple. RCG decided to make Mac gay because McElhenny's family has personally struggled with homophobia.

18. DeVito only joined the show because his kids were fans.

After season one, FX only agreed to continue Always Sunny if a big-name celebrity was added to the show to draw in more viewers. DeVito was offered the part of Frank Reynolds, and only accepted because his kids loved the show. He didn’t plan to become a main cast member, but loved the set so much that he decided to stay.

19. DeVito nearly died on set.

During the last two episodes of season 11, “The Gang Goes to Hell: Part One” and “The Gang Goes to Hell: Part 2," the gang partakes in a series of events that leads to them getting locked in the jail cell of a Christian cruise ship. When the ship sinks, the gang are left for dead. They give up on trying to save themselves, and decide to float to the bottom, hold hands, and spend their last few moments with each other. Eventually, they are saved.

According to an interview with Day, DeVito kept floating up during this scene. The crew strapped weights to his body so they could get the shot. At the end of the take, everyone got to the top of the pool safely except for DeVito, who was being pulled down.

Thankfully, a dive team was on set and was able to save him.

Thanks for reading!