If you ever want to feel old, all you have to do is remember that It's Always Sunny in Philadelphia has been on for 13 seasons, with a 14th expected to premiere on FXX later this year. And after spending nearly a decade and a half with the Gang, it's easy to slip into their same habits — specifically the way they talk about Dee (Kaitlin Olson), the only girl in the group of delinquents who run Paddy's Pub. While everyone takes their turn being the ultimate f---up of the episode, there is no doubt that Dee, even when she should have the high ground, will always slip right back down to the bottom of Sunny's social hierarchy. Because while Charlie (Charlie Day) eats cat food and huffs paint, Dennis (Glenn Howerton) is most definitely a rapist, Mac (Rob McElhenney) doesn't believe in evolution, and Frank (Danny DeVito) legitimately killed someone, Dee's otherness as a woman is unbreachable and unchangeable.

This isn't some accidental example of misogyny, but a purposeful choice by the show's writers and executive producers, which include Day, Howerton and McElhenney, who married Olson in 2008. It's Always Sunny uses Dee — and the Gang's mistreatment of her — to do what the series does best: comment on the depravity of humanity by showing people at their absolute worst, and no member of the Gang is immune to their peers' offensive behavior or biases. That's why you'd be hard-pressed to find an episode of Sunny in which the rest of the Gang doesn't disparage Dee in ways that specifically play off her womanhood — attacking her appearance and ability to attract men (or lack thereof) — without ever singing her praises.

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Unfortunately, fans often discuss Dee the same way the Gang does, laughing at the latest pitiable action from the big bird without ever articulating just how fantastic Olson is at playing this character, who has so far stolen a dumpster baby, seduced a priest, set her roommate on fire, and tricked a stripper into humping his daughter's face.

An aspiring actress with no shred of talent or morality, Dee is a force of nature who violently plows ahead toward a future she dreams of but is destined to never achieve. She is unruly, shameless, and borderline sociopathic, and we don't often get to see women acting just as badly as Dee on TV — or at least we didn't when Sunny premiered in 2005. Dee's abhorrent behavior was refreshingly grotesque when the series first hit FX 14 years ago (it moved to FXX starting with Season 9), and one could make the case that Dee helped pave the way for the vulgar female narcissist that is now commonplace in modern television (see: Veep's Selina Meyer, Fleabag's titular heroine, You're the Worst's Gretchen Cutler, and literally any character in Girls). But this wasn't supposed to be the case. As most Sunny fans know by now, originally Dee was supposed to be the voice of reason, the feminine "straight man" who would help put the Gang's bad behavior in perspective. Not interested in playing such a bland archetype, Olson initially turned down the part before approaching the creators with the suggestion that they make Dee just as funny, over the top, and offensive as the guys. This note changed the entire trajectory of the character of Dee — and the show — for the better.

Yet when people talk about celebrated modern comediennes, Kaitlin Olson is rarely mentioned. But as Dee, Olson is demonstrating a range that you can only fully grasp by watching the entire series — all 144 episodes and counting. She delivers something wildly different in each episode, and sometimes even in each scene within a single episode. She excels at both heartbreaking self-loathing and blustering overconfidence, twisted wit and naive gullibility, broad physical comedy and subtle asides. She turned a synchronized dance with an inflatable tube man into one of the most memorable physical bits in the past 10 years and has delivered some lines of dialogue that really should be inscribed in stone outside historic buildings.

But what really makes Dee so truly special is the humanity that Olson brings to the role. Driven by a deep-rooted fear of failure and an unshakable need to be accepted, Dee is a like a funhouse mirror reflection of exactly who you don't want to be but who you're afraid exists deep, deep inside you. Dee responds to these insecurities by being in constant competition with the rest of the Gang, unwilling to admit or perhaps completely blind to the fact that she will never come out on top. Because at the end of the day, no matter what Dee does or if the guys do the exact same thing, her gender will always mean she's about to get knocked right back down... not that Dee ever goes down without a fight.

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In Season 8's "The Gang Gets Analyzed," we get a peek into Dee's psyche when she brings her friends to her therapist (Kerri Kenney) so a neutral party can decide who will do the dishes. After meeting with the rest of the Gang, Dee's therapist calls out her client on lying about her life in therapy to make it sound better (although, could her therapist ever really have believed Dee was originally cast opposite Ryan Gosling in The Notebook?). When Dee finds her constructed reality challenged — not to mention her acting skills — she completely melts down, vacillating between pitifully begging the therapist to give her validation and forcefully demanding it. In the end, when the entire Gang demands an answer about who will do the dishes, the therapist follows the lead of everyone else in Dee's life and uses her as the scapegoat, officially naming her as the one who has to clean up everyone's mess. At that, the rest of the Gang walks out of the office laughing while Dee stays behind verbally assaulting her therapist, all the while breaking each of the dishes in question at her therapist's feet.

One could examine how Dee's abuse of others is an example of the cycle of abuse, with the perennially put-down Dee projecting her rage at her abusers onto others. But it's really not that deep. Dee is just an inherently bad person, just like every member of the Gang. And it's fantastic to see a woman be unapologetically bad, offensive, foul-mouthed, and straight-up disgusting even 13 seasons in because Olson manages to keep Dee feeling fresh. While the character never truly changes (the entire show would fall apart if any of the characters exhibited any noticeable growth) Olson makes sure each burst of rage, each begrudging defeat when the Gang knocks her down, and each dry heave is slightly different than what we've seen before.

So if we're going to give Julia Louis-Dreyfus a record-setting six Emmys for calling Jonah the "Jolly Green Jizzface" in Veep, can't we at least give Olson and Sweet Dee a little bit more love, too?

It's Always Sunny in Philadelphia is available to stream on Hulu.

Kaitlin Olson, It's Always Sunny in Philadelphia Photo: Byron Cohen/FXX

This week, TV Guide is celebrating some of TV's most underrated female characters. As part of Women's History Month, we're paying tribute to The Vampire Diaries' fierce witch Bonnie Bennett, looking at why Dear White People should put more respect on Joelle's name,and more. You can check out all our Women's History Month content here.