I've come to this thread late and everyone is mentioning pretty obviously good shows which won awards etc. But there are 2 criminally underrated shows which were just phenomenal when I watched them:

The Americans - in my opinion it should be up there with the other big shows like The Sopranos and The Wire etc.

The Patriot - tv series .. not the stupid Mel Gibson movie. Amazing premise and probably not as popular because of a stupid name and Amazon.

Oh and bonus show: The Bear. But it's getting the accolades it deserves.. so knew it would be good going in

Band of Brothers and Pacific

Definitely Steven Universe. Random, ignorant people love to shit on that show just like random, ignorant people love to shit on the entirety of the furry fandom; and it does start more childish and unserialized. But hot damn does it get good later, and it was one of the most-helpful, intelligent, and positive experiences of my life.

Among many things I COULD talk about, I would just like to add that I've never seen a more thorough and accurate portrayal of autism than Peridot; and they don't ever outright say what they're doing with her, but even the green alien symbolism is there. Also how people respond to her, both positively and negatively, as well as her ability to learn to improve— so smart and good.

Since I watched Series 4 in 2021, I don't think a week has gone by that I haven't watched an episode, or at least a clip, of some iteration of Taskmaster.

The American version of shameless. I didn't like the English version but the American one was really entertaining.

Dora the Explora.

Fucking hell that’s some DEEP shit.

I check reviews before watching stuff so there’s not a lot, but I remember going into Mad Max Fury Road blind and was blown away. The Killing of A Sacred Deer as well, but I was already aware of Yorgos and his style, I just didn’t know if the movie was good or not.

Heat

Lars and the Real Girl. It sounds like a risible premise that is actually super human and skillfully executed.

Dr Who

Before I watched the "New Who" episodes on the stern recommendation of an obsessed girl friend, I was extremely reluctant.

I just saw more and more friends and aquatences go into watching the series, normal as one can be.

Them, they watched the series on Netflix.

It changed them, giving them an almost unhealthy level obsessed obsession with the show.

I too had the same change, but on a much less level than some.

My somewhat spolier-lite to spoiler-free reccomendations:

Ghost in the Shell: Stand Alone Complex. I'd also recommend the original movie, but it's kind of a different beast.

Really well done series that switches between long expository plot sequences, and really well done action sequences, in a pretty good display of budgetary efficiency. The plot exposition, dialogue, and investigative stuff kind of surrounds the action scenes with an actual sense of consequence and meaning, relative to most anime that I've seen, and the series as a whole is kind of much more grounded than most other anime, which is also incredibly refreshing. The medium is used in this case more to emphasize subtle differences between this potential near-future reality and our own, rather than kind of just, being an engine for bombastic and outlandish animation and repetitive trope-work. The series bounces between episodically structured plots, or, stand alone episodes, and episodes that deal with an ongoing seasonal plot, or character plot, and there's a couple little progressions in there that kind of span the series if you're paying attention. There's not really any arcs, it's just a good, focused show, front to back.

The Venture Bros.

Slow start, but it's also probably one of the better pilot episodes, in my mind, of all time. Plenty of little comic book nerd references in there that are pretty enjoyable, and the comedy is pretty good at times while also tending not to venture into the offensive, except for maybe two or three instances that stand out in my mind, which is maybe somewhat impressive for an early adult swim show. I think, more than that, though, the series' ability to juggle serial plots and episodic plots is kind of mind blowing and insane. One-off episodes and single characters get spun off into entire fully formed characters with arcs and backstories. Stupid jokes get expanded into much larger things than you would expect. It's very well done.

Nichijou

Yeah, this one is pretty good, you should watch it.

Drive and District 9.

Deadwood

Arcane

If you’re a fan of gritty police dramas, I continuously beat the drum for The Shield. It’s one of most tightly written series I’ve ever seen, with events from the very first episode affecting everything that comes after. Plots wind through multiple episodes and sometimes seasons.

All 7 seasons are currently on Hulu.