Developing characters in unexpected ways has been It's Always Sunny's strength, and Charlie and the Waitress have had a lot of surprising moments.

Charlie and the Waitress have the most complicated relationship of any two characters in It’s Always Sunny in Philadelphia. Now, some would argue that the two don’t even have a relationship since Charlie has stalked the Waitress for years and she’s shown no romantic interest in him. But the term “relationship” is more broadly defined than the official classification that Facebook has given it.

It’s been surprising to see how much their relationship has developed over the years, in spite of keeping their stalker/victim dynamic intact. Developing characters in unexpected ways has always been the show’s strength. So, here are the 10 Most Important Moments In Charlie And The Waitress’ Relationship.

10 The Waitress Overhears Charlie Saying A Racial Slur

In the pilot episode of It’s Always Sunny, “The Gang Gets Racist,” we first meet the Waitress and see her disdain for Charlie as she overhears him using a racial slur at the coffee shop. Charlie is using the word to quote Dee’s new African-American boyfriend – although whether or not he should use it even when quoting someone is also a hotly debated issue – but the Waitress hears it out of context and immediately calls Charlie “Hitler.”

Of all the things we’d see Charlie do in the future to offend the Waitress, this one at least doesn’t have permanent psychological damage – but it’s the first one we ever saw.

9 The Waitress Sleeps With Frank

In the season 2 episode “Mac Bangs Dennis’ Mom,” Charlie gets an idea to woo the Waitress when he finds out Mac has slept with Dennis and Dee’s mom. He realizes that if he gets the Waitress to believe that Dennis is sleeping with Mac’s mom and his own mom, she’ll be so jealous that she’ll want to sleep with him to get back at Dennis.

And while he does succeed in getting the Waitress to fall for it, she decides to sleep with Frank instead of Charlie (this was back when Frank was thought to be Dennis’ dad). Dennis doesn’t care, but Charlie is heartbroken.

8 The Waitress Becomes Charlie’s Alcoholics Anonymous Sponsor

The Gang is required to do community service in the season 2 episode “The Gang Gives Back” following their acts of arson and borderline terrorism in “The Gang Goes Jihad” – one of the few times that the Gang is shown facing consequences for their actions – and Charlie is made to attend some Alcoholics Anonymous meetings.

There, he learns that the Waitress is a recovering alcoholic and sees an opportunity to spend some time with her. She becomes his sponsor, but it later becomes clear that she’s only doing it to get close to Dennis and Charlie goes back to drinking.

7 Charlie Proposes To The Waitress After The Nightman Cometh

In the season 4 finale “The Nightman Cometh” – the best episode of the whole series, according to some fans – Charlie puts on a musical starring the Gang and invites the Waitress to see it. He promises her that if she comes to the show and stays until the end, he’ll never bother her again.

So, just to get him off her back, the Waitress comes to the show and, at the end of it, Charlie reveals the ulterior motive that the Gang suspected he had the whole time. He arrives on the stage and sings a song that ends with a proposal to the Waitress. She says no, Charlie is heartbroken, and he says that since he didn’t sign anything, “I’ll see ya tomorrow?”

6 Charlie Finds Out The Waitress Is Engaged

The season 5 episode “The Waitress is Getting Married” mostly revolves around Dee’s attempts to break up the Waitress and her new fiancé Brad out of jealousy. However, the B-plot sees Dennis and Mac trying to get Charlie on the dating scene to avoid him going postal when he finds out about the engagement. So, they get him on an online dating site and set him up on a date that goes horribly.

The engagement does break up, as it turns out Brad is just dating the Waitress to break her heart as revenge for breaking his in high school. But for a brief moment, Charlie had to come to terms with the possibility that his window to seduce the Waitress had closed.

5 The Waitress Takes Ecstasy & Spends A Night With Charlie

In the season 7 episode “The Gang Goes to the Jersey Shore,” Dennis and Dee unwittingly become a part of a drug-fueled crime spree, while Mac and Frank get stranded at sea. The only member of the Gang who has an enjoyable night is Charlie, who is joined by the Waitress on the beach. They spend a great night together, finding little knick-knacks in the ocean and sleeping together on the sand.

The following morning, when Charlie is riding high on the greatest night of his life, the Waitress is horrified to find him lying next to her and explains that she took ecstasy the night before and didn’t mean anything she said.

4 Charlie Uses Ruby Taft To Make The Waitress Jealous

When Charlie and Dee land dates with members of the wealthy Taft family, Dennis assumes it’s a ploy to humiliate them in front of their rich friends. Dee’s new boyfriend turns out to be using her in such a ploy, but Charlie’s new girlfriend Ruby Taft – played by guest star Alexandra Daddario – turns out to be getting scammed by him.

She genuinely likes him and has been enjoying dating him, but it turns out he’s just been using her to make the Waitress jealous, and when the Waitress calls him from the hospital and promises to shorten the distance of her restraining order against him, he dumps Ruby on the spot.

3 Charlie Endures A Minute Of Emotional Battery From The Waitress

Sequels to episodes have become quite common in TV comedies: Rick and Morty gave us “Interdimensional Cable 2: Tempting Fate,” Community gave us “Advanced Advanced Dungeons and Dragons,” and How I Met Your Mother gave us “Slapsgiving 2: Revenge of the Slap.” It’s Always Sunny has given us two sequel episodes: “Gun Fever Too: Still Hot,” which followed up on season 1’s commentary on the gun issue, and “Chardee MacDennis 2: Electric Boogaloo,” which brought back the Gang’s fan-favorite board game.

Sequel episodes tend to ratchet up the tension. In this case, Charlie had to withstand a full minute of emotional battery from the Waitress without crying – and he caved immediately.

2 Charlie & The Waitress Sleep Together

Due to the nature of running gags in sitcoms, It’s Always Sunny fans never thought they’d see the day when the Waitress agreed to sleep with Charlie. In the season 12 finale “Dennis’ Double Life,” Dennis reveals that he has an ongoing relationship with a woman he impregnated during the Wade Boggs challenge.

Realizing that pregnancy is a one-way ticket to commitment, Charlie decides to convince the Waitress that she needs a baby. Much to his surprise, she’s taken with his offer and they sleep together. And, even more surprisingly, afterward, she says, “That was not as bad as I expected.”

1 Charlie Loses Interest In The Waitress

This is another moment we can file under “totally unexpected turns.” Having pined after the Waitress for 12 years, Charlie finally got to sleep with her. And not only that, she was committed to moving in with him and starting a family.

But the second the sex was over, he lost interest in her. He didn’t want to start a family with her, he didn’t want to live with her, and he didn’t even want to take her phone calls. It’s Always Sunny fans have been surprised by a lot of developments in Charlie and the Waitress’ relationship, but how quickly Charlie lost interest in her takes the top spot.

NEXT: It's Always Sunny: 10 Ways The Gang Has Changed Since Season 1

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