Asklemmy

Do games count? I would say Halo 3.

Endgame is the end of the MCU. After endgame disney pished out too much MCU shit and ruined it. They should’ve stopped at endgame and not try to make many shows that also factor into the overall MCU. Some may argue that this problem was already too much before endgame premiered. That is a valid argument.

S10 E12 (The Doctor Falls) is the end of (Modern) Doctor Who. Such a perfect episode epitomising the character, and closing an arc for one of the longest villains. He even 'dies' at the end.

Everything since then has been badly written and purposefully disrespectful to the cannon and the audience, and has wasted so many fantastic actors.

I only wish I ever learned who's the mother and how he met her...

Terminator 2 (T2) is a masterclass in combining CGI with practical effect and its ending is a rare cinematic full stop.

The T-1000’s liquid metal form was revolutionary, the morphing effects were cutting-edge in 1991, yet Cameron used them sparingly and only where practical effects couldn’t work. That restraint made the CGI more impactful and has made it so they still hold up 35 years later.

The truck chase through the storm drain, the helicopter flying under an overpass, the Cyberdyne building blowing up; it was all real and you can feel that when you watch the movie. There is no way any movie studio would do that nowadays when they could just CGI giant Michael Bay explosions.

The destruction of Cyberdyne and the Terminators meant the timeline was reset. Judgment Day was averted. The T-800 lowering itself into molten steel is an iconic moment; a machine choosing self-sacrifice for humanity. It’s a perfect final note, not just for the character, but for the franchise. Bringing him back again and again weakens that sacrifice. Any sequel has to undo all of this just to exist. Which is why to this day, I have not watched a single Terminator film after T2.

Futurama - Meanwhile

The "new" episodes they released afterwards don't count. I acknowledge that they exist but I do not grant them the title of canon.

24 Season 4 is my version of a happy ending. I'm not saying I didn't enjoy the rest of the show, but God damn, Jack didn't deserve that many bad days.

Toy Story 3.

EDIT: And to elaborate, the movie showed a conclusion to a longer narrative thread of Andy growing up and his toys needing a new home. There was a satisfying ending.

Aliens ended the franchise. Slightly different answer, nothing occurred between the release of Predator and Prey.

I feel compelled to say Scrubs s08e19, which is weird because they only ever made eight seasons of Scrubs.

The Matrix

The Office when Michael moved away. It was never the same after that.

Last episode of The Simpsons Season 9

Episode 25 of Death Note would have been a dark, but logical place to end the series. After that point the entire dynamic of the show changes. There are some good and interesting moments, but it doesn't really feel like the same show.

Season 5 of Supernatural was the logical endpoint

The last harry potter movie (deathly hollows pt 2) marks the end of the franchise as far as I am concerned. 8 great movies and 7 great books. I wish there was more but I fail to see how it can be extended. Both fantastic beasts and crushed child do more harm than good to the original franchise

Season 1 of Westworld. It’s okay to have an ambiguous ending, you can leave it to viewer’s imagination. That show went downhill with every season because it was trying too hard to be smart.

Babylon 5 ended with season 4 and the excellent shadow war arch.

Rocky ended at Rocky. Even Rocky 2, the second best movie if you're judging its qualities with the same ruler Rocky's measured, feels off compared to the original. Rocky is a love story/character study with a little bit of boxing at the beginning and at the end, whilst the rest are boxing movies primarily/solely.

Also, while everyone knows Terminator ended with T2, did you know Kung Fu Panda also ended with KFP2? 🙏

The Office when Michael left.

Terminator 3 is the last of that series in my eyes. The others - although not too shabby (excluding Salvation of course) - I regard as fan fiction.

Arrested Development - that last season just did not agree with me.

Community - things dropped off quickly when Troy left.

I know your question is worded for movies and shows but I have one example from the world of video games that still makes me sad. Final Fantasy died shortly after X, maybe X-2. XII if you really want to stretch things. After that, they were too focused on "modernizing" gameplay. I just want something with a colorful world, quirky characters and turn-based combat that's more about finding the right strategy for a boss than reflexes.

I guess XIV is nice in its own way but as an MMORPG I see it more as a spin-off than as a part of the main series. The VII remakes tickle some nostalgia neurons but would have been better without their real-time combat. XIII, XV and XVI were just meh. If you really want to make me happy, make a faithful remake of VIII with modern graphics, rebalanced but otherwise faithful gameplay and a few more scenes in the last act that answer a few questions that the community has been trying to answer for 25 years.

Walking Dead S07E01. I think that episode could have been a perfect ending. They dragged it a lot after.