The 1990s and 2000s were really the peak of teen television entertainment. If the 1980s had been the decade of movies made for teens, the subsequent two decades showed a marked turn toward entertaining teenagers on the small screen, as well.

While the 1990s were filled with soap after soap, including 90210 and Melrose Place, the television of the 2000s zeroed in on the stereotypical high school melodrama unlike any other era of television before it.

With shows like Dawson's Creek and One Tree Hill captivating audiences with their tales of tormented teens and risque relationships, the high school soap opera had never been in stronger form.

In 2003, Fox decided to try something a little different, introducing The O.C. as part of its lineup. Equal parts privileged kids and underdogs, the show -- at the beginning, at least -- tried to offer interesting social commentary across the generations, all while providing the requisite soapy fare that had proved popular with teens.

Over time, however, the commentary faded, making room for one of the soapiest, messiest teen dramas to ever air on television. As dark as the series got in its pursuit of peak teen melodrama, it's no surprise that some equally shocking things went down behind the scenes.

Here are the 15 Behind-The-Scenes Secrets Even True Fans Didn't Know About The O.C.

15. Mischa Barton and Rachel Bilson didn't get along

Although they were often at odds with one another for the sake of any number of contrived, short-lived dramatic conflicts, Summer Roberts and Marissa Cooper were one of the strongest friendships to come out of The O.C., and the early 2000s teen drama genre in general.

With none of the backstabbing and boy stealing that is found in other teen series (we're looking at you, One Tree Hill), their friendship was truly supportive and compassionate.

However, all was not so rosy behind the scenes of The O.C., as rumors about Mischa Barton and Rachel Bilson's mutual disdain for one another have existed ever since the series began.

In a 2004 interview with ELLE Magazine, Barton took a few cheap shots at Bilson's appearance and personality, noting that "She's way more overtly s*xual than I am. She is so petite and I'm so tall and lanky. I think I'd be scared of having her voluptuousness. I like being understatedly s*xy."

14. Ryan was originally Sandy Cohen's illegitimate son

One of the most successful parts of The O.C. is, without question, the found family forged between the Cohen clan and Ryan, who they take in out of the goodness of their own hearts.

Sandy's connection with Seth and his quasi foster son Ryan is genuinely heartwarming, imbuing the over-the-top series with something grounded in warmth and love.

However, had the original plan for the dynamic been maintained, things could have gotten a whole lot more twisted for the Cohen-Atwood family.

In original concepts outlined for the series, Ryan was meant to be Sandy's illegitimate son. Given how beloved the relationship between Kirsten and Sandy was, however, it's hard to imagine the show ever having gone through with that idea.

Therefore, in many ways, the decision to scrap that idea was most definitely for the better.

13. Mischa Barton purposefully spoiled Marissa's passing

In this age of the internet, social media, and nonstop entertainment coverage, spoilers are hard to avoid, especially when it comes to the most popular shows and movies.

When The O.C. was airing in the early 2000s, however, the internet was just beginning to reach the peak of what it was capable of in that area, and social media was year's away.

However, that didn't stop one particularly major spoiler being let out just before the third season finale of The O.C. -- and even worse, a spoiler let out by the departing cast member herself.

Mere hours before the finale in which Marissa was cut off would air, Barton went on Access Hollywood to confirm the rumors that had been swirling about for months at that point -- that Marissa was being cut off, and that she, therefore, would be leaving the show.

12. Cam Gigandet and Ben McKenzie feuded behind the scenes

As part of The O.C.'s head-scratcher of a third season, numerous characters were introduced who truly didn't ever add much of anything. One of those was Kevin Volchok, a bad boy with no redeeming qualities whatsoever who just had to take up with the poor, reckless Marissa.

Naturally, as a rival for Marissa's attention and affection, Volchok and Ryan sparred frequently on screen. However, as it turns out, some of that tension seems to have extended off of the sets as well, as Cam Gigandet has reported in recent years that he and Ben McKenzie did not get along-- at all.

Still, he doesn't harbor any resentment toward him: "Ben McKenzie was kind of mean to me. I hadn't done anything at that point and he was a little bit of an a**. But I love him. I think he's a great actor and I love Southland."

11. The teen cast was sick of the show by season three

For young actors who find themselves thrust into the public realm on a grand scale, with no warning at all, navigating the transition from obscurity to fame can be quite difficult.

According to Tate Donovan, who played the perennially toxic and unstable Jimmy Cooper on the series, the kids found themselves gaining something else in addition to fame: a real sense of superiority.

As Donovan explained in a 2013 interview with Vulture, commemorating the show's tenth anniversary, "the kids on the show had developed a really bad attitude. They just didn’t want to be doing the show anymore."

He continued: "It was pretty tough; they were very tough to work with. The adults were all fantastic, total pros. But you know how it is with young actors — and I know because I was one of them once. When you achieve a certain amount of success, you want to be doing something else."

10. Peter Gallagher thought the show was politically brave

The early 2000s were a fractious time for the country, and pieces of entertainment media did their best to reflect that adequately. As it turns out, the political weight of a show like The O.C. was, in fact, what attracted leading man Peter Gallagher to the series.

As Gallagher has reiterated time and again over the years, he was drawn to the story as depicting a post-9/11 world of unity and integration, a world full of acceptance in the face of prejudice.

With the Cohens as successful New York Jews in a very upper class, WASP-y section of California, and taking in a teen who was worse off than they were, the series was, in some surprising ways, incredibly progressive for the time -- despite rarely casting a person of color in a major role during its entire run.

9. The show was meant to be a gritty police or sports drama

Early ideas are often best left on the cutting room floor. Knowing what The O.C. could have been had Josh Schwartz's original ideas been kept only further confirms that fact.

Before deciding to tell the story of the dark side of the affluent world of Newport Beach, other ideas that Schwartz considered included a gritty drama about sports, or yet another hard-hitting police procedural with a darker tone.

Thankfully for fans of The O.C. everywhere, both of these ideas were scrapped in favor of the long iconic campy fare that the beach sudser turned out to be.

For anyone who wanted to see a little bit of what could have been, leading man Ben McKenzie has almost exclusively taken leading roles in gritty police dramas ever since.

8. Josh Schwartz based the show on his own life experiences

In many ways, The O.C. functions as a dual outsider story. Obviously, the show is about the kid from the wrong side of the tracks being given a chance on the right side when the Cohen family takes Ryan in and raises him as one of their own.

However, within that outsider story is nested another, more socially savvy one: the depiction of a Jewish family within a primarily WASP-based community.

As it turns out, much of the inspiration for that idea came from Josh Schwartz's own life experiences as an east coast Jewish kid who moved to the west coast in order to attend USC.

As he explains it, in his own early experiences in California, he "felt very much like a stranger in a strange land when I got there... I felt very much like an outsider, and it was always interesting because you’d go to a football game in the daylight and it was always hard to tell who was the mom and who was the daughter, and everybody was very preppy, well-dressed... Then, when the sun went down, the kids were living a very different lifestyle than what they were presenting."

7. Summer and Julie were meant to be recurring characters

It's hard to know which characters are going to work in a series before anyone has seen it, or before you realize just how much you enjoy writing for them.

In the case of The O.C., two characters clearly took on lives -- and fan bases -- of their own, and became so much more than they were ever intended to be.

Rachel Bilson's ditzy darling Summer Roberts speaks all of three lines in the pilot episode. However, those three lines were enough to win audiences over, and by the seventh episode, she was a full-fledged series regular.

Similarly, Melinda Clarke's delightfully devious Julie Cooper was only a recurring guest star for the show's first few episodes, before also being upgraded to series regular midway through the first season.

6. Ben McKenzie wasn't the original choice for Ryan Atwood

Casting is as crucial a part of creating a series as the actual act of writing it. If the wrong person is cast for the wrong part, there's no coming back from it.

Re-casting can assuage some missteps that may have been taken along the way, but the initial mistake can't be undone.

Thankfully, The O.C. made the right call in their casting of future Commissioner Gordon Ben McKenzie in the role of Ryan Atwood, the ne'er-do-well from the wrong side of the tracks and with a heart of gold.

Earlier versions of Ryan's character could have had far different faces, with the likes of onetime teen heartthrobs Garrett Hedlund and Chad Michael Murray both having been considered for the role prior to McKenzie's casting.

5. Olivia Wilde was the runner up for Marissa

In retrospect, it's hard to imagine anyone else in the starring roles that became so instantly iconic. Could we really see anyone else filling Summer Roberts designer shoes, or brooding the way that Ryan Atwood was born to brood?

However, as we've already seen so far, Ben McKenzie wasn't the first choice for the broody bad boy from Chino. As it turns out, Mischa Barton wasn't guaranteed the role of Marissa Cooper, either.

Before they decided on giving Barton the role, Marissa was very nearly played by future Alex Kelly actress Olivia Wilde.

However, as much as the powers that be behind the series loved Wilde's acting, they realized that she would come across as too strong and put together, when they needed a Marissa who was far more vulnerable and in need of saving.

4. The network requested the show up the melodrama for the third season

Shows hitting sophomore slumps is a common phenomenon. However, it's not as often that you encounter a show that loses its way in the third season.

However, that's exactly what happened for The O.C. -- and as it turns out, we really have the network to thank for that one.

According to Josh Schwartz, the network requested the addition of new characters and increased ridiculous drama for the sake of heightening the melodrama.

"We were just told we had to add an adult female character. It went nowhere, and we had no plan for it, and it just didn’t fit the show," he said. "And then we went down the wrong road with this kid playing Johnny. It was just flat. All of a sudden, everything the show mocked, it kind of became."

3. Josh Schwartz didn't want to cast Adam Brody

It's one thing to know that Ben McKenzie and Mischa Barton weren't the original guaranteed actors for the roles of Ryan and Marissa. The star-crossed couple were such a crucial part of the short-lived cult hit that it's hard to imagine any other duo captivating audiences quite the way they did.

However, it's another thing entirely to learn that Seth Cohen -- arguably the series' biggest breakout character -- was almost not played by Adam Brody. Also, further, that Josh Schwartz in particular initially hated him for the role.

As Schwartz recounts, "When he first came in to audition, it was pilot season and he was going on dozens of auditions, and he didn’t really bother to learn the lines, so he just came in and I was like, 'What scene is he doing? Is this even from our show?'"

"We tried to find other actors, and our casting director, Patrick Rush, told me, 'I’m telling you, this Adam Brody is very special.' And I thought, “That guy? I kind of hated that guy. He didn’t even learn any of the words,'" he said.

2. Alex and Marissa were meant to have a more meaningful relationship

LGBTQ representation is becoming more and more commonplace in media these days, especially in movies and shows targeted at the coming of age demographic.

However, when resident waif Marissa Cooper began a short-lived relationship with bad girl Alex Kelly, it was a galvanizing moment in terms of representation of an underrepresented population.

Thanks to the network's interference, though, it turns out that we never truly got to see their relationship as it was intended to be portrayed.

According to Josh Schwartz, the network insisted Olivia Wilde be written out of the series earlier than planned due to concerns with the storyline.

Adding insult to injury, the relationship as it was had already been cut to pieces for the sake of marketing it as a ratings trick, with a crucial romantic scene having nearly 75% of its content cut due to network concerns.

1. Josh Schwartz regrets cutting Marissa out

In recent years, cutting out lead characters has become increasingly common, with varying degrees of success and fan outrage to show for it, depending on the case.

When The O.C. decided to cut Marissa off in 2006, however, to Schwartz, it seemed like the right thing to do.

"We felt like we had told those stories and that this was always kind of in Marissa's DNA. That she was a tragic character and that try as he might, Ryan ultimately wasn't going to be able to save her," he explained in 2013, before noting that his opinions regarding the decision are now more complex.

"What I learned after that night was those critics [who hated Marissa] were in much smaller number than the millions of people who watched the show and loved that character. And there was a real sense the morning after of 'OMG. What have we done?'"

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What other secrets behind the making of The O.C. do you know about? Let us know in the comments!