Which longer than 2 season series has been the most consistent through it's run?

Game of Thrones (with the exception of 8th season)
Mad Men (never once dipped in quality to me)
Breaking Bad (see Mad Men)
The Sopranos
The West Wing (with the exception of 7th season)
Seinfeld (with the exception of last episode)
The Boys
er (Seasons 1-8, after Edwards left)

The Shield
The Wire

Also, The Mandalorian.

Oh, forgot a pretty big one on Amazon

Frasier
Bosch
Person of Interest
Breaking Bad

Superstore is consistent throughout its 6 seasons. Can't recall a bad season.

Also, shoutout to Greek and its 4 seasons. Miss that show.

I'm not sure you can include something that is still ongoing, unless you can also include like any three seasons of a show that went to crap in other seasons. So you really need a show that maintained a high level of quality, was popular enough that it didn't get cancelled after one season (RIP Freaks and Geeks) and called it quits before that quality dipped, which seems exceedingly rare for a US broadcast network show... there are probably more British shows (with less episodes per season) or cable "prestige" shows, but the networks will milk something popular until it's dry.

That said, you still get something like the Good Place which had a plan and stuck to it, or comedies like Malcolm in the Middle which stayed pretty consistently funny throughout.

The thread says 2+ but I think the OP doesn't want to include ones that only went 2 seasons and stopped? So no Chapelle Show?

If we can include cartoons or anime, I'd say there are a bunch more. Dini and Timm's Justice League, Nick's Avatar, Venture Bros., Gravity Falls, Adventure Time, Clone Wars, Duck Tales (old or new) etc.

Breaking Bad
Black Sails
​​It's Always Sunny (I don't care what anyone says!)
Seinfeld
Jeopardy!
Raising Hope

Batman: The Animated Series- one of my favorite animated shows of all time and love Conroy as the voice of Batman.

Breaking Bad- really never had a bad episode in my view. Very consistent throughout. I expect to put Better Call Saul in this category but I haven’t watched it all yet.

Curb Your Enthusiasm- solid all around. Haven’t watched the newest season yet, but really good overall.

Seinfeld- a few episodes aren’t my favorite, but I still enjoy even some of the lesser episodes and at its best it’s one of my favorite shows ever.

Six Feet Under- I enjoyed all five seasons.

Star Trek: The Next Generation- one of my all time favorite shows. Rocky at first but gets good in season two and progressively better.

Star Wars: The Clone Wars- maybe one of my favorite things in all of Star Wars and gave me much more of an appreciation for the prequels.

According to Jim
CSI

I agree. CSI and the new CSI Vegas have been very consistent throughout it's run. It's one of the most consistent crime dramas of the last 20 years.

But, I know many in this forum love to hate/mock it because it's on CBS and it's deemed an old person's show.

I'll also add that NCIS has been a very consistent show entering it's 20th season. Both shows wouldn't be on that long if people hated it.

Agree that Mad Men never had a weak season.

Loved every moment of Big Love.

Looks like Barry is 3 for 3 so far.

Old school shout outs to Thursday night staples Cheers and LA Law as well as St. Elsewhere and The Practice (which doesn’t get the respect it deserved)

ER until Edwards left.
DS9 after Brooks shaved his head. S4-end

Santa Clarita Diet
Bob's Burgers
The Spectacular Spider-Man
Flight of the Conchords

I'll suggest The Magicians if you can discount the final fifth season a bit. Four quality seasons before they wrote out a certain character.

The Shield. The seasons get better or remain high quality throughout the series. Same with The Sopranos.

I've been rewatching the entire 11 season run of Cheers and it's truly remarkable that there isn't a single bad episode or season. I'm down to the last half of season 11. Some are funnier than others but that's a helluva run without a dip. I guess the closest you could say would be season 6, the first with Rebecca. She was kind of a terrible character that season but got better the following season.

Brooklyn 99 is another comedy that just unbelievably consistent for 8 seasons, that even some of more well regarded shows can't claim (Friends, Seinfeld, Parks and Rec, Community and even Arrested Development had dips).

USA can claim a few for this discussion; White Collar, Burn Notice and Psych we're all good, start to finish.

And I'll also toss out some love for Fringe and Chuck.

Beavis and Butthead

Trying to stick to the question, all I can think of is Person of Interest and Fringe. I liked both of those a lot and can’t think of any seasons that I considered noticeably better or worse than the rest.

Lots of shows have a streak of 2 or more seasons equal in quality, but that’s not ‘for its entire run.’

Likewise, I’d say a lot of the good-to-great shows listed here actually varied in my opinion. A show that’s seasons you would rank 7, 10 and 8 is actually varying more than something you’d give a 6, 6 and 6, even though you fully consider the former to be better.

Grimm
Stargate SG-1

Fringe
Grimm
Warehouse 13
Eureka
12 Monkeys
Haven
Continuum
The Good Place
Schitt's Creek