Perhaps more than any other long-running primetime drama series in recent history, Grey's Anatomy truly revitalized the notion of the plot twist, and just how important a component it is to the creation of a successful, addictive series.

With twists now happening at an astounding rate, it's easy to forget that the earlier episodes were slower, and less surprising in some regards.

However, as the series became more and more popular, and as fans grew all the more invested in the soapy medical series, it became clear that the twists and the cliffhangers would work in their favor. Well, for the most part, at least.

Certain plot twists-- such as the introduction of a character, or the beginning or ending of a romantic relationship-- tend to work more strongly in terms of garnering fan loyalty and interest.

However, other ideas-- including shocking, callous deaths for beloved characters, written purely to shock the audience-- have burned the series time and again.

Yet, Grey's still stands, nearly fourteen full seasons later and with no sign of slowing down its crazy pace of twists and turns any time soon.

Here are the 8 Plot Twists That Hurt Grey's Anatomy (And 7 That Saved The Show).

Hurt: George's passing

George O'Malley acts surprised about Derek's romp in Grey's Anatomy

Arguably the first sign that Grey's Anatomy would truly hold nothing back when it came to hurting its fans, George's passing at the end of the series' fifth season remains one of the most infuriating and upsetting decisions that the series has made to date.

George, adorably affable and hapless in every way, was the closest the original team of residents had to a real heart.

By getting rid of him so suddenly, the series soon lost much of its warmth in turn.

Admittedly, there were certain behind-the-scenes factors at play here in the decision to write O'Malley out of the series in such an abrupt way.

However, no part of any offset drama could possibly excuse the traumatic, gruesome, and overly detailed way in which George passed away.

Saved: Burke leaves Cristina at the altar

Cristina and Burke look at each in Grey's Anatomy

Of course, George's departure wasn't the only one primarily driven by behind-the-scenes matters. Dr. Preston Burke's abrupt exit at the end of season 3 was, of course, motivated by rumor after rumors of disputes between Isaiah Washington, cast members, and Shonda Rhimes herself.

However, while George's exit from the show proved detrimental to its overall narrative, Burke's exit allowed one of the show's strongest characters-- Cristina Yang-- to grow so much more than she had until that point.

By allowing Burke to leave Cristina at the altar, Grey's set up years upon years of strength and growth for Cristina that we may never have gotten had the doctors married as intended.

Also, by allowing Cristina to grow stronger in all those years, her decision to accept a position working alongside Burke so many years later is all the more rewarding.

Hurt: Callie's new girlfriend is responsible for Derek's passing

Penny and Callie sitting at the dinner table in Meredith's house on Grey's Anatomy

Grey's asks a lot of its viewers when it comes to suspending their disbelief in highly unrealistic medical and emotional scenarios.

However, perhaps one of its most unforgivable decisions in that regard was to pair Dr. Callie Torres in a romantic relationship with Dr. Penny Blake, one of the doctors who had been responsible for Derek Shepherd's untimely death.

It would have been one thing had the reveal of Callie's poor choice of a significant other been used as a moment of shock value, leading the new couple to break up and avoid all the messy complications that came with this coupling.

However, the series stuck by this unfathomable couple, even sending Callie off to live with Penny in New York with little Sofia following Sara Ramirez's decision to exit the series.

Saved: Addison's introduction

It was the cliffhanger ending that shocked viewers and passionate Meredith/Derek fans everywhere: season 1 of Grey's Anatomy ends with the reveal that Derek's estranged wife, Addison, has arrived at Seattle Grace.

Addison would go on to be a polarizing character for many, but there's no denying that the introduction of her character injected the series with some much needed tension.

Stakes were now raised much higher for the fan favorite but as of yet unstable couple.

Furthermore, in the process of creating Addison's character, Grey's was able to resist taking the simple way out. While occasionally shrill and villainous, Addison was allowed to become a fully-formed character of her own, and not just a new obstacle in the way of Meredith and Derek's relationship.

Hurt: Owen's presumed deceased sister returns

Kevin McKidd and Bridget Regan as Owen and Megan Hunt in Greys Anatomy

As we've already seen, characters reappearing again out of virtually nowhere isn't exactly unheard of on Grey's Anatomy. However, when all signs point to those never before seen characters having been deceased, and then they suddenly resurface, that's quite a different matter.

The truly bizarre, uncomfortable, and seemingly never-ending plot involving Owen Hunt, his sister Megan, and Nathan Riggs took up far more narrative space than it should have.

Thankfully, Megan would be written out eventually, taking Riggs along with her for good measure and eliminating another source of difficult scenes.

Making matters worse, the series was forced to recast the role of Megan as a result of scheduling conflicts, which led to both Bridget Regan and Abigail Spencer appearing in different capacities as Owen's sister.

Saved: Mark's introduction

Eric Dane Greys Anatomy

Being introduced as a character who's only out for himself and stands in direct opposition to the male lead isn't an enviable position for any new character in a series.

However, somehow Mark Sloan managed to do the impossible, winning over the audience even as he proved himself to be quite the jerk to start.

The man who was once Derek's best friend-- and would become his best friend again, in time-- was only initially a source of further conflict for the rocky marriage between Derek and Addison.

However, over time, Mark's character was allowed to develop from McSteamy into a much more mature, emotionally open one.

Through his rekindled friendship with Derek, as well as his star-crossed romance with Lexie, Mark would prove over time that his introduction was one of the best decisions Grey's ever made.

Hurt: Denny returns as a ghost... again

Izzie keeps seeing Denny's ghost in Grey's Anatomy

Grey's isn't afraid of getting spiritual, in many senses of the word. In one of the series' most iconic episodes, Meredith briefly exists in a world between life and death, having allowed herself to drown for a short period of time.

While in that state, she is visited by the recently deceased Denny Duquette, past flame of fellow resident Izzie Stevens. In that context, the appearance of a familiar face is genuinely affecting, allowing some of Meredith's most resonant development in the process.

However, the series tried to tap into the ghost Denny well once again in season five with a meandering, unbearably awkward plot with Izzie seeing him and becoming romantically involved with his ghost on numerous occasions.

Unfortunately, as a result of this, the use of Denny's character in this capacity undid any good that the character had done previously.

Saved: Callie and Arizona call it quits for good

Callie looks angry at Arizona in Grey's Anatomy

On the whole, the relationships depicted in Grey's Anatomy are hardly worth aspiring to emulate in real life. Often filled with lies, betrayal, and manipulation, the couples in the series have been consistently portrayed in as soapy a manner as possible.

When it comes to the relationship between Callie and Arizona, however, these slights and faults are all the more troubling.

For years, the couple was hailed as true progress for LGBTQ representation; but in later years, the progressive message they were heralded as putting forth was lost behind layer upon layer of manipulative behavior, infidelity, and a grueling custody battle that nearly ruined both characters in the process.

Thankfully, the series made the correct decision in the end, having the long-time couple cut things off for good in season 11-- a decision that became all the more permanent with Sara Ramirez's exit.

Hurt: Cristina's exit

Meredith and Cristina in Grey'a Anatomy

Truthfully, there was nothing remotely out of character about Cristina Yang's departure from the series. Ever ambitious and brilliantly bold, it came as no surprise that she would choose to pursue her career and her dreams, even if it meant moving half a world away from all those closest to her.

What was most troubling about this twist of events, however, was what came next.

Due to Sandra Oh's desire to leave the series after all of those years, the show was forced to work through future traumatic events that affected Meredith without the benefit of having her best friend, her person, right by her side as she always had been.

A body double was awkwardly used in the instance of Derek's death, but beyond that, Cristina's complete absence from the narrative is one that has provided harder and harder to accept over time.

Saved: Addison's departure, and the creation of Private Practice

Henry and Addison Private Practice

As previously discussed, Addison was always a polarizing character during her tenure on Grey's. The decision to allow her character to exit the series, and in turn have a series all her own, therefore, was undoubtedly a brave one on the network's part.

However, in doing this, they were able to solve two big problems all at once.

Grey's no longer had so difficult a figure to contend with, and what's more, Addison was allowed to truly come into her own and be the lead of her own story on Private Practice.

Running for six seasons, the series showed a more vulnerable side of Addison than Grey's had ever been able to show, allowing her character to fall in love and find family and happiness in the process.

Hurt: Richard and Ellis had a child

Maggie Pierce smiling on Grey's Anatomy

Sometimes, when a show has clearly been on the air far too long, plot twists begin to appear that signal the writers have run out of steam and are just looking to throw in whatever shocking, nonsensical ideas they think of.

For Grey's Anatomy, this can be seen more clearly than anywhere else in the form of Maggie's character-- and more specifically, the reveal that Dr. Richard Webber and Dr. Ellis Grey had a secret child that no one had ever known about for all of these years.

It was one thing when Grey's expanded Meredith's family through a half-sister the first time around. However, unlike Maggie, Lexie was a likable, well-acted character.

However, from the moment she was introduced, Maggie has never once fit into the narrative, sticking out like a sore thumb and creating conflict after conflict just by existing.

Saved: Meredith and Derek's spur of the moment wedding

Derek and Meredith smiling on Grey's Anatomy

After five long seasons of dancing around one another and struggling to be together, it finally seemed as though Derek and Meredith were headed toward their happily ever after.

A wedding was in the works, and things were looking up for the perpetually troubled pair.

However, when it became apparent that things weren't going as planned for their nuptials (as if they ever could, at Seattle Grace), Derek decided to try things in a truly unique way, as only such a unique couple deserved.

Through the form of writing a contract of vows on a Post-it note and signing it to seal the deal, the couple unofficially wed themselves to one another.

They vowed that they would be together forever, regardless of the legal precedence of their wedding documentation.

Hurt: Mark and Lexie's passsings

Over its many, many seasons, Grey's has shown that it's not afraid of potential fan backlash, especially when the passing of beloved characters are concerned.

However, undoubtedly two of the most difficult moments fans were forced to endure-- back to back-- were the losses of the "meant to be" couple of Lexie Grey and Mark Sloan in the season eight finale and season nine premiere.

The plane crash arc took its toll on many, many characters who roamed the halls of Seattle Grace, and undeniably changed the series from that point onward.

However, more than anything else, it was the sudden loss of the couple who so deeply loved each other, yet were never able to fully find their way back to one another, that hurts the most to this day.

Saved: Lexie's introduction

Chyler Leigh as Dr Lexie Grey in Grey's Anatomy

Grey's has never shied away from introducing characters who are meant to shake up static dynamics, whether positively or negatively. However, when they introduced Meredith's half-sister, Lexie Grey, at the end of the series' third season, they likely had no idea just what a great asset they would be getting in return.

Meredith may have been the series' titular heroine until that point, but with the addition of another Grey, the show became that much better.

Lexie was everything that Meredith struggled to be: emotive and warm, full of heart and compassion, and always willing to listen to her heart above her intellect.

Through Chyler Leigh's portrayal, Lexie brought necessary levity and heart to the series, eventually taking up the space for character-driven emotional narratives that would be vacated by T.R. Knight's departure from the series.

Hurt: Derek's passing

Derek Shepherd in Greys Anatomy.

There was no way that any other item on this list could have possibly been considered the number one plot twist that ruined everything that Grey's Anatomy once stood for.

By cutting out Derek's character, the series once again proved itself to be living in a world devoid of heart and hope.

For Meredith Grey to be forced to endure yet another senseless loss, after all she had already been through, showed the true ugly nature of the series' perverse enjoyment of making its characters miserable.

Not to mention, by removing the series' leading man, Grey's was down in strength of cast and characters, and has yet to rebound from that creative mistake, no matter how many new male characters-- and Shepherd family members-- it has tried to shove into the narrative ever since.

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What plot twists do you think saved and ruined Grey's Anatomy over the years? Let us know in the comments!