TV shows can run for years. Sometimes they get canceled while still in their prime. Other times, they drag on and on, losing whatever it was that made them special in the first place. We've all had that experience of falling madly in love with a show, only to become sad when it prematurely gets the ax. Similarly, we all know what it's like to give up on a program because it's just not going anywhere new anymore.

Sitcoms are especially prone to these problems. A really funny show that's forging new ground risks getting yanked off the air before audiences have had a chance to get used to its comedic rhythms and develop an appreciation for its innovation. Any time you're doing something deeply original, there's a chance that it will take a while to catch on. At the other end of the spectrum, sitcoms can have trouble maintaining their spark over the years. They can repeat jokes and scenarios, or resort to desperate attempts to liven things up.

Below are those sitcoms that were canceled earlier than they needed to be and others that need to ride off into the sunset. These aren't just any sitcoms, though. They're some of the most iconic ever to grace the nation's television screens. We'll tell you the stories of why their early demises were unwarranted, and present arguments for why they've hung around too long.

Here are 12 Iconic Sitcoms That Were Canceled To Soon (And 8 That Need To Go).

Canceled Too Soon: Arrested Development

Arrested Development main cast

Arrested Development has had an incredibly bizarre life. It initially ran for three seasons on the Fox network, picking up status as a "cool" cult show without ever breaking into the mainstream. In fact, it was pretty regularly one of the lowest-rated programs on the air at the time. Fox cut the number of episodes ordered for both the second and third seasons as a result.

Critics were baffled by how such a high-quality show could go so unloved. Then an amazing thing happened. Arrested Development came out on DVD and found an appreciative audience.  Based on that triumph, Netflix revived it in 2013, and so far there have been two additional seasons. A happy ending indeed for the Bluths.

Needs To Go: Modern Family

The entire cast of Modern Family holding a photo frame and posing for a photo

Modern Family was a hit right out of the gate. As positive word-of-mouth grew, the show saw its ratings increase during the second, third, and fourth seasons. The show revitalized Ed O'Neill's career years after Married With Children went off the air and made stars out of Sofia Vergara, Sarah Hyland, and Eric Stonestreet.

At its peak, the program pulled in more than twelve million viewers a week, according to the Nielsen ratings. Recently it seems that audiences are getting fatigued with Modern Family. Season nine, for example, found it drawing only seven million viewers weekly -- a sizable drop. It's safe to say the program will never again be as popular as it once was.

Canceled Too Soon: Parks and Recreation

Donna, Chris Pratt, Aubrey Plaza, Adam Scott, Amy Poehler, Aziz Ansari, Nick Offerman, and Jerry in One Last Ride - Best Parks and Rec Episodes

Despite low ratings, Parks and Recreation managed to hang on for seven seasons, thanks to raves from TV critics and the ongoing of its dedicated fans. Series co-creator and executive producer Michael Schur wanted to go out while the show was still on top, as did star Amy Poehler. When they mentioned an exit strategy to NBC, the network jumped at the chance to pull the plug.

As any dedicated viewer knew, though, Parks and Rec was getting better all the time. It continually evolved into one of the sharpest pieces of political satire ever put on television. We can only imagine where the show might have gone had it been allowed another season or two.

Needs To Go: Will & Grace

Megan Mullally, Eric McCormack, Debra Messing, and Sean Hayes in Will and Grace

Will & Grace was a big deal when it hit in 1998. The show dealt with LGBT issues in a way that had never occurred on broadcast television before. Over time, it earned a whopping 83 Emmy nominations. The sitcom aired for eight seasons on the peacock network, ending with a final episode that attracted a reported 18 million viewers.

Revivals of old shows are the hot thing right now. Will & Grace came back for a second round in 2017. Ratings have been decent, but nowhere near what they were before. That's likely because other shows have taken what it originally did to the next level. What once was cutting edge now just feels like a watered-down version of itself.

Canceled Too Soon: Freaks and Geeks

Freaks and Geeks Cast

Freaks and Geeks is the stuff legends are made of. Produced by Judd Apatow and created by Paul Feig, the '80s-set show was an insightful look at what it was like to grow up in a decade where obsessing over Saturday Night Live, Star Wars, and Steve Martin comedy albums was considered uncool.

NBC bounced the show around so much that it could never grow an audience. The network canceled it after just one season, letting a cliffhanger ending go unresolved. Years later, Freaks and Geeks became a cult sensation, thanks to the eventual stardom of cast Seth Rogen, James Franco, and Jason Segel. It's now considered by many to be one of the greatest comedies ever aired.

Needs To Go: South Park

South Park character lineup

South Park first aired all the way back in 1997. Since then, it has had twenty-two seasons totalling nearly 300 episodes. The show was a groundbreaking piece of animation -- one that contained crude, envelope-pushing humor and a penchant for targeting sacred cows. It spawned a successful 1999 feature film, subtitled Bigger, Longer & Uncut, in addition to a series of videogames.

The problem with something like South Park is that, the longer it goes on, the less it maintains its counter-culture edge and the more it becomes part of the establishment. In other words, it loses the ability to shock. Even hardcore fans it that the last few seasons have been wildly inconsistent in quality. At this pace, the longer it goes on, the bite it once had will continue to fade.

Canceled Too Soon: Taxi

Taxi had the dubious distinction of being canceled twice. During its four-season run on ABC, the show -- about a handful of colorful NYC cab drivers -- won three Emmys as Best Comedy series. It also earned great reviews and solid ratings. Nevertheless, the network decided to give it the ax in 1982, to the surprise of just about everyone.

HBO floated the possibility of picking up Taxi after ABC dropped it, but ultimately opted not to. NBC stepped in, even giving the show its same time slot, Thursdays at 9:30. A year later, the cast found the show canceled once more. Despite being tossed by two different networks, Taxi was named one of TV Guide's 50 Greatest TV Shows of All Time.

Canceled Too Soon: Gilligan's Island

gilligan's island cast

It's hard to believe, but Gilligan's Island only aired for three seasons. Despite that brief run, the show has become one of the most iconic sitcoms in the history of television, living on through several TV movies and spinoffs, including a mid-'70s animated series.

The story of its cancellation is rather sad. Although ratings dropped somewhat in the third season, CBS promised everyone that it would renew the show. Then the network decided to make a last-ditch effort to save the long-running Western Gunsmoke by moving it to a different time. CBS axed Gillian's Island and gave Gunsmoke its slot. The cast were reportedly devastated by the news that they were out of work.

Needs To Go: The Big Bang Theory

The Big Bang Theory cast

When it premiered in 2007, The Big Bang Theory was right on the cusp of the "nerd" revolution that was about to take place in America. Things that had once been marginalized -- like intense interest in superheroes and science fiction -- were coming into the mainstream in a big way. The show felt incredibly timely.

Now in its twelfth season, the joke has run its course. Critics of Big Bang often gripe that the show feels as though it's repeating the same jokes over and over, with only slight variations. The idea of nerds as heroes also no longer has the freshness that it once did. It's surely time for Sheldon and the gang to call it a day.

Canceled Too Soon: 30 Rock

Despite significant acclaim, multiple Emmy awards, and general pop culture pervasiveness, 30 Rock was never a particularly big hit. In fact, during its third and most popular season, it was only the 69th most-watched show on major network television. It cast a large footprint, despite having mediocre viewership.

While the quality of 30 Rock could be hit-or-miss, it never failed to take chances. Even when it did have a weak episode, that was usually because it took risks that simply didn't pay off. Too many shows are afraid to take risks at all. There still seemed to be plenty of places for Liz Lemon and her colleagues to go when the show signed off in 2013. It's too bad we won't get to see what those destinations would have been.