The series finale is not just the end of a season. The final episode of any show--from short-lived single seasons to long-running, much-loved TV classics--is a chance for writers and showrunners to deliver something truly memorable and satisfying, giving audiences a payoff that will have them thinking about those final minutes for long after. From M*A*S*H and Cheers to Breaking Bad and The Americans, some of the greatest, most powerful episodes of any TV shows have been series finales.

But of course, there are those series finales that get it very wrong. In some cases, the bad end can be predicted for some time. Shows that have gone on way too long, often shedding viewers, cast members, and showrunners until they are finally put out of their misery by the network. In these cases, terrible final episodes were just the last in a long time of bad episodes, with seemingly little interest from everyone involved in making it good.

There are also bad series finales to shows that were still good, that totally fail to deliver what fans were expecting. Sometimes there are dramatic and bizarre narrative decisions that leave fans scratching their heads, and others times just a reluctant shrug that says “will that do?” And of course, some shows ended terribly simply due to sudden cancelation, with no opportunity for writers and producers to wrap things up properly. But in every case, these were not the endings that fans had hoped for, and are now remembered as truly terrible conclusions to often great shows. So here's our rankings of the worst ever...

10. Lost

Let's face it, was Lost ever going to have a satisfying conclusion? After nine season, the writers had tied themselves in so many narrative knots that delivering a final episode that kept the majority of those still watching happy was always unlikely to happen. But that's no excuse for the lazy, sentimental cop-out that we did get, in which viewers were presented with a confusing, boring vision of the after-life and an explanation for the “Flash-Sideways Universe" that no one really cared about to start with.

9. ALF

This episode was intended to be a cliffhanging season closer for the ‘80s alien comedy, not the end of the entire of the show. But there would never be a fifth season, leaving fans with one of the saddest endings in mainstream sitcom history. The final scene sees ALF is about to be reunited with his Melmacian buddies, who are descending, ET-style, in a spaceship. But the sudden arrival of the Alien Task Force scares them off, leaving ALF surrounded by sinister agents who have been hunting him for years. And that's it. Even though ALF cracks a few jokes to his captors, the mournful music and bleak tone of this entire sequence makes for a truly tragic final episode. The storyline was belatedly wrapped up six years later in the TV movie Project: ALF, but that was small comfort for a generation of traumatised ALF fans.

8. Seinfeld


7. Weeds

Some great TV shows slowly turn bad over many episodes--and some make a sudden, dramatic downturn. Weed is a firmly in the latter camp. After three hugely entertaining, witty and engrossing seasons, the suburban satire about a pot-selling widow took a nose dive in Season 4 and became increasingly ridiculous. Unfortunately it would be another four season before Weeds was put out of its misery, with a extremely poor final episode that lazily wrapped up all the hanging story threads by simply zooming forward to eight years to a point where everyone's life is pretty much sorted. While no one likes a load of unresolved storylines, this is not the way to do it.

6. True Blood

Another show that started brilliantly but ran for way too long, True Blood's finale was truly terrible. By time this episode rolled round, the once weird, transgressive, daring show had become a vampire soap opera, complete with easily resolved conflict, overwrought melodrama, and an awful flash-forward happy ending that revealed that Sookie was happily married to... some guy we'd never seen before. A series fully deserving of the stake through its heart.

5. Roseanne

You know a series finale is bad when the show's revival many years later pretends it never happened. Roseanne's original run ended with the “twist” that the entirety of the final season had never happened, and that Dan had died from the heart attack he suffered at the end of Season 8. The entirety of Season 9 was, in fact, Roseanne's imagined perfect version of her life, in which Dan is alive and Connors won the lottery. The season didn't work because in celebrating wealth it was everything that the show was not, but the ending that explained it all was even worse.

4. Quantum Leap

To be fair to Quantum Leap creator Donald Bellisario, this episode was not intended to be the final one for the iconic ‘90s sci-fi time travel show. With NBC cancelling the series before the episode aired, some hasty reshoots were made that gave the whole show a vague resolution that made no one happy. The overall concept wasn't terrible--Sam Beckett leaps into his own body--but it never delivers on the promise that this would be the episode where everything is explained. Instead we got an episode padded with characters from earlier seasons but no sense of conclusion. Worst of all, the show's famous tagline and promise: "hoping each time that his next leap... will be the leap home." is completely betrayed by the final title card: "Sam Beckett never returned home." Huh?

3. St. Elsewhere

For many years the final episode of the iconic ‘80s hospital drama was unchallenged as the having the worst ever episode. After six seasons of tears, laughter, and engrossing character-based medical drama, audiences were given the absolute nadir of all TV twists--it was all a dream. Or more specifically, it was an imagined fantasy in the mind of Tommy, the autistic son of Dr. Westphall. Known as the 'Snowglobe ending', there has been some suggestion that it was a meta-commentary about the fact we are all knowingly watching fiction. But trying telling that to fans who had stayed the course only to find that everything they had watched to that point was utterly meaningless.

2. Dexter

As Dexter limped into its eighth and final season, it was becoming a bit of struggle to remember why it was so good to start with. Sure, Michael C. Hall's performance was still strong, but for the most part this was a messy, incoherent season that paid off almost nothing that had been set up in the previous one. But the worst was saved for last, a woeful conclusion in which packed with stupid twists, idiotic moments (Dexter stealing Deb's body?), tedious flashbacks, and THAT final scene where it's revealed that Dexter has taken up a new life as a sad-looking lumberjack. No.

1. How I Met Your Mother

A classic case of a final episode that betrayed absolutely everything that the show had spent nearly a decade building towards. After nine long years, we discover that it doesn't really matter how Ted met his kids' mother, because she's going to die a few minutes after being introduced to the audience. And then he's going to get back together with Robin, even though their relationship never worked in past and she was recently married to his best friend, Barney. Whose wedding we just spent the entire season at. What?