Why do so many TV shows have terrible endings?

Because it's easy to write intrigue and hard to pay it off. You don't have to have compelling answers to write compelling questions.

B/c they rarely have control over when they end.

It's much easier to set up a premise than to architect a story and build to a payoff that satisfied everyone. Plus writers tend to care more about thematic payoff and fans tend to care more about plot payoff.

Hated Ozark ending. I stared at a dark screen for 2 minutes mad.

(If you're looking for a show with an unbelievably satisfying ending, try Mr. Robot.)

Nailing the landing is just about the hardest thing to do in any endeavour and writing TV shows is no different.

Writing is difficult, sticking the landing in a satisfying way is even more difficult

I think there is something fundamentally difficult about making a good ending to a TV series simply because the creative process is continuously ongoing as the show airs. Unlike a movie where you can take everyone's input and create a final work that satisfies most, or all, of those involved, a TV series has different seasons with different writers, showrunners, directors, executive producers. I imagine that lack of continuity makes it difficult to end a story well.

I think it's a mixture of fans overhyping themselves into expecting something different to what they get.... And sometimes shows having to wrap up big stories quickly as they've been given the heave ho. Two of the most annoying for me are Stargate Atlantis and Legends of Tomorrow. Atlantis because they had a 2 part cliffhanger story they set up to span seasons and SyFy cancelled it and didn't let them have an extra episode to finish the story, so everything was rushed into one episode. Legends of tomorrow because they left it on a cliffhanger that was never resolved in any of the other shows.

It often happens that the creator of the show envisions how they want it to end from the very beginning. But when the show runs for multiple seasons and naturally changes over time (relationship developments, long-terms arcs, new characters and storylines, etc) the ending they'd originally planned back in S1 no longer works for it, yet they just use it anyway with no regard for that. *Ted Lasso* is probably the most recent one that springs to mind in that case.

Part of it is that writing is hard. Setting up mysteries is easy, but solving them in a compelling way is much tougher. Another part of it is that TV is a medium in which you write stories over the course of years, often without knowing exactly when the end will come or when an actor is going to become unavailable. You also have to get people hooked right away, which incentivizes creating a lot of tension, drama, and intrigue immediately so you get viewers and get renewed. When you write a book or a movie, typically someone buys the whole thing at once. They usually don't have the option of paying per chapter and choosing to bail if they aren't drawn in (or if they bail, they already spent their money, so it isn't a huge loss).

TV shows often don't get to choose how many episodes they have, they risk every season being the last, so they may be ending earlier or later than planned and some start with no plan. Some plans get ruined by budgets or actors quitting. So building a series of interweaving storyline designed to all crescendo at the same time to beautifully resolve into a well orchestrated finale is difficult. Well seasoned and regularly hired writers are the ones who can churn out those near stand alone entertaining episodes that have a mere hint at an over-arching plot. And if you have a BBEG. Do you diminish every season/season finale from all but the ultimate season by excluding a battle with the BBEG. Do you have a lesser evil to defeat each finale. A cliffhanger. Does the BBEG win every prior season? Plus, do you make the finale the relatively predictable "baddy defeated, good mostly win, some emotional loss" which is what people mostly want, but will also feel obvious. Or do you go with "subverted expectations" and have the baddies win (never happens) or do you have the one that occasionally happens "everything the heroes work for was a lie, they have been misled and puppeted, and at the last minute the real goal changes" - and that diminishes all previous seasons. Or the worst of all, the 1st grader story twist "it was all a dream, simulation, alternate timeline, hallucination, "purgatory"" and it was essentially a meaningless story.

Game of Thrones for sure.

How I Met Your Mother is up there.

Hard to beat Dexter or Game of Thrones. X files was also terrible but less annoying 

Recently, From. Garbage after I loved the premise and story. I can think of 20 different shows that are still running, I guess they still have time to not END terribly, but seasoning finales were terrible

I think there is a decent chance the boys ends decently, they’ve known for a long time this would be the last season. Seems like a lot of shows dont know the last season really is the last until fairly late or its not their choice idk. Anyways, as long as Homelander gets a real good comeuppance i’ll be satisfied lol I think probably Sopranos ending annoyed me the absolute most. To the point it numbed me to an extent to decades of mid to bad show endings

I think it’s funny that in the season 5 finale of Supernatural, the narration by Chuck says outright that anyone can write a beginning, but endings are the hard part. Then that show ran into the ground for ten more years.

I think writers paint themselves into a corner and there is no way out, which leads to a bad ending.

It's really difficult to write consistently well over the course of many years for that many episodes, especially as a lot of your best ideas inevitably get used up by s3 or so. The longer the show goes on, the more it just becomes a stable paycheck for the cast and crew rather than a labour of love. With that many people involved, you get behind-the-scenes drama, studio medalling etc. that all result in a decline in quality of time. So therefore, the few shows that stick the landing tend to be on the shorter side, have a succinct main idea, while being decently plotted out in advance. But the vast majority of TV shows ever aired were done with the mindset of keeping them on as long as it's pulling high ratings and therefore remaining desirable to advertisers. Ergo, the hope tends to be is that the ending works for the characters you've come to know and love rather than answering every question ever posed in the show.

Do they? I think most shows have good endings. A separate issue is that most shows just get worse over time.

Shows seem to either end too early or run to long. It's only when a showrunner has a plan from the start for the series with a specific number of seasons that things seem to work.

Let me hit you with a different line of thinking. So you think of terrible endings like GOT but was it really a terrible ending or a continuation of the poor quality of the final season? Because even though I liked the first 2 episodes and thought The Long Night was a cool event episode, episode 4 of GOT season 8 was the point where you knew you were watching poor trash. Usually bad final seasons have had endings because they're already bad! I'm thinking of Dexter, Oz, and The 100 of other examples I've seen. More rare to have a bad final season and great ending. I'm thinking of Buffy and Lost.

Because it doesn’t end how people want it to so they get mad and downvote equivalent it and people like lemmings jump on the hating bandwagon. For example Ted Lasso.

Writers aren't writing tv to complete a logical and coherent story. And at this point, they are writing for viral memes and for the immediate buzz and clicks. As Lost was wrapping up, I knew the ending would suck and was still disappointed.