After seven seasons as the world's best and simultaneously worst boss, Michael Scott, Carell left the NBC sitcom. "I just think it's time," he told us at the time. "I want to fulfill my contract. I just thought it was time for my character to go." Viewers, sadly, did not think it was time as the show suffered in the ratings and creatively, as no one, including Ed Helms and James Spader, was able to fill the void left by the funnyman.
Did Carell ever return? Oh yes, he did. Michael Scott made one final appearance in the series finale, serving as best man at Dwight and Angela's wedding, and doling out one final, "That's what she said."
Let's be honest, fans are still reeling from Will Gardner's shocking and truly upsetting death in season five. Even more shocking? The cast and crew were able to keep it a secret for over a year. Of his decision to leave the series (co-star Julianna Margulies actually convinced him to stay longer than he had originally planned), Charles said, "I thought that I felt however much I've enjoyed the experience, I was ready for the next chapter of my life, both creatively and personally."
And while The Good Wife is still going strong, and adored by critics, it's hard not to miss the passion and intensity that Will brought to the show. Also, we'll never not wonder "What if..."when it comes to Will and Alicia.
Has Charles ever returned? Only to direct the episode dealing with the fallout from Will's death. And it seems unlikely that he will, considering creators Robert and Michelle King made a point of killing Will, not sending him away.
"We could ‘send him off to Seattle,' he could be disbarred, or get married, or go off to Borneo to do good works. But there was something in the passion that Will and Alicia shared that made distance a meager hurdle," they said. "The brutal honesty and reality of death speaks to the truth and tragedy of bad timing for these two characters."
Edelstein's season seven exit from the medical drama was sudden and swift, leaving House (Hugh Laurie) and Cuddy (Edelstein) shippers seriously ticked off. (He drove his car through her house!) Season eight, the series' last, just wasn't the same without Cuddy.
"After much consideration, I am moving onward with a combination of disappointment at leaving behind a character I have loved playing for seven years and excitement of the new opportunities in acting and producing that lie ahead," Edelstein said in a statement at the time.
Did Edelstein ever return? Negative.
After completing his three-year contract, Stevens asked to be written off the BBC period drama, and what an exit it was. Fans were devastated when Matthew Crawley died. In a car crash. In the Christmas special. After Lady Mary (Michelle Dockery) had just given birth to their son. Since his season three demise, Downton just hasn't felt the same, especially since Matthew and Mary's relationship was one of the series' most important elements.
Has Stevens returned? No, and it probably will never happen.
OK, it wasn't exactly surprising that Marissa Cooper died in the season three finale, given Barton herself spoiled the death in an interview. What was surprising, however, was how much the series needed its poor little rich girl. Season four just wasn't the same without the original core four. Sure, Autumn Reeser's Taylor Townsend turned ino a charming addition, but it just wasn't the same.
Did Barton ever return? Nope.
Sheen was infamously was fired from the hit CBS sitcom in 2011 after a public meltdown in which he lashed out at producer Chuck Lorre, with his character Charlie Harper being killed off the show. His replacement? Ashton Kutcher. Still, the show never quite recovered from the loss of Sheen. (Sorry, Jon Cryer!)
Has Sheen ever returned? No, but his character kind of has? Kathy Bates appeared as Charlie Harper (seriously) in 2012, and won an Emmy for it. Heading into its final season, Sheen is hoping to make one last "classy" appearance on the CBS series, but sources tell us that it's not happening.
Glee's quarterback, on and off-screen, tragically died of a drug overdose in July 2013 at the age of 31. The producers, with the OK of star Lea Michele, Monteith's girlfriend, made the decision to have Finn die on the series, and had a tribute episode in season five.
"It was really emotional because I really loved Cory. And Brad [Falchuck] and I and Ian Brennan, who created Glee, all had very close, good relationships with him," Ryan Murphy told us at the time. "He passed away not so long ago, and we sort of were in a position where, what do you do when that happens? So we chose to write a tribute, not just to the character Finn that he played, but to Cory."
As Glee's heart and soul, the loss of both Finn and Monteith has colored the rest of the series.
You don't think of ER without thinking of Dr. Greene. From the early days to his final hours, he was the heart of the hit medical drama. The character died during season eight of the NBC drama, succumbing to a brain tumor. The ER staff cried. We cried. You cried. ER was no stranger to cast departures by the time he left the show, but Dr. Green's death—the only original character to die—stung and sent ER down a new path for the next seven years.
Did Edwards ever return? Edwards reprised his role in the final season in 2008 for a flashback episode where he interacted with Angela Bassett's character.
While he's died several times on the show, his season three death (and eighth on the show) was a permanent one. (Well, as permanent as a death can be in Mystic Falls.) And we definitely felt his loss, as well as the characters as Elena and Jeremy seriously needed a parental figure and Damon needed a BFF/drinking buddy.
Has Davis returned? Alaric made frequent visits as a ghost before Davis returned to the series as a regular for its sixth season. Huzzah! Prayer really does work, people!
This one is definitely polarizing, as Buffy went on for another four seasons without Angel, but many fans felt that season three, Boreanaz's last as a series regular, was the cult hit's peak. Boreanaz, of course, left to star in his own spinoff series, Angel, which ran for five seasons. (Can we just imagine for a second the freakout if a show did that today in the Twitter-age?!)
Did Boreanaz ever return? Angel returned to Sunnydale multiples times throughout the rest of the series, including the infamous "cookie dough speech" in the series finale. We wonder if Buffy, who made a memorable guest turn on Angel, ever finished baking?
While the medical drama has lost plenty of doctors and patients throughout the seasons, none cut quite as deep as the loss of Knight's George O'Malley, one of our O.G. interns. And the way it happened,
Has Knight returned? Sadly, no.
It was bad enough that Spiderman 3 was a movie at all, and it was made even worse by the fact that it took Topher Grace away from That 70's Show for its terrible final season, during which Fez and Jackie got together, Kelso moved to Chicago, and Hyde married a stripper. Eric was "replaced" by a truly awful character named Randy (Josh Meyers), but we don't like to talk about Randy.
Did Grace ever return? Eric returned for a cameo in the series finale, but he could not undo the damage that Randy had done to the show (and our hearts).
Oof, this one still hurts. Though Dex took down the Trinity Killer, played by John Lithgow, in the season four finale, the baddie managed to make one final kill: Dex's wife, Rita. Seriously, who still isn't haunted by the image of Harrison playing in her blood? While it stands as one of the series' best moments, it's also the moment the signaled the downfall of the show. Curse you, Trinity!
Did Benz ever return? negative.
What happens to Laverne and Shirley when Shirley leaves? That was what viewers asked when Cindy Williams departed the iconic sitcom and it wasn't exactly amicable. A lawsuit and settlement followed, but for Laverne and Shirley's final season there was just Laverne (Penny Marshall), with Shirley hastily written out. Not the ideal way to end a series, but everything's all good between Laverne and Shirley now!
Did Williams ever return? Nope.
Charming's death toll has always been high, but it never felt more real than when Jax's (Charlie Hunnam) best friend Opie died, brutally being beaten to death in front of him, in season five. His death changed Jax, the club and the show forever, with creator Kurt Sutter even saying, "The death of Opie will color the rest of the episodes for the rest of the series." And it has.
Has Hurst returned? Nope, but Jax did pay Opie's grave an emotional visit in the season six finale.
While Pitt exited the series almost three years ago, fans are still not over his character Jimmy Darmody's shocking death at the hands of Nucky Thompson (Steve Buscemi), his mentor. There were rumors of Pitt being difficult to work with, but creator Terrence Winter denied the claims, telling EW, "Michael is a total professional. He's intense, of course, but I don't think you can do that job without being intense."
Has Pitt ever returned? No, but Pitt has an idea for how he'd like the series to end. "I think my son should assassinate Nucky Thompson," Pitt told us. "My son is about 11 now. Yeah, he needs assassinate Nucky."
PHOTOS: The 20 most shocking deaths in recent TV history
TV lost one of the greatest dads ever when 8 Simple Rules patriarch John Ritter suddenly and tragically died of a previously undetected heart problem at 54. Instead of recasting the role (because no one would ever be as amazing as Ritter), after a hiatus the show decided to write in his death, and showcased how a family deals with grief. It was a heartbreaking, raw, authentic and emotional storyline that was done right, but the sitcom never recovered despite adding David Spade and James Garner as series regulars.