I still watch it at times but I end up fast-forwarding through the “I fail at shopping” first day to get to the “Surprise, here we are! OK, here’s what we meant with our examples” second day.
E.R. is the major one I stopped watching that comes to mind, but I can’t remember any longer when it was. It did get too repetitive.
Heroes seems to be the runaway winner (loser?) of this one. It’s on my list too - I gave up early in season 3, once it became clear that the crappiness of season 2 had less to do with the writers’ strike (as the show’s producers claimed) and more to do with running completely out of ideas.
I gave up on Studio 60 pretty quickly, maybe 5-6 episodes in, once it became obvious that Sorkin was using the show as a none-too-subtle way for him to air his dirty laundry.
Family Guy has sucked out loud ever since its resurrection. I am praying that Futurama doesn’t meet the same fate.
Scrubs is a show that started so strong, then over the course of about three seasons, gradually eroded into a pathetic, unfunny shell of its former self. By the time I stopped watching, sometime in season 6, it was hard for me to remember what I’d liked about the show in the first place. Fortunately, rewatching episodes from the first two seasons reminded me that it wasn’t that the show always sucked, but that they had long since forgotten what once made it good.
The Office is on a similar (but, thankfully, slower) downward spiral. It hasn’t crashed into outright suckitude yet, but it’s been hovering in the murky fog of mediocrity for about three years now.
My Name I Earl was good to watch sometimes until they sent him to jail. Jail killed the show for me.
I used to watch Grey’s Anatomy religiously but all of a sudden realized that all the characters are annoying. I’ve given up on Law and Order: SVU but will still watch it in reruns if I’m bored. CSI I just don’t bother with any longer. My “must sees” are Justified, The Closer, NCIS and In Plain Sight so I just don’t have enough spare time for shows that make me go meh.
I don’t really give up on shows. If I don’t like the actual watching of the show anymore, I record it and fast forward through most of it, getting an idea of the plot, just so I won’t be totally lost if it ever gets good again.
CSI - like a few others, i pretty much stopped watching when William Peterson left, although even before his departure i had started missing some episodes. I don’t watch either of the stupid spinoffs.
Law and Order - Fontana and Green (Dennis Farina and Jesse Martin) was basically the last pairing that i watched with any consistency. I watched a few after Green’s injury, but haven’t watched a new episode in ages now. I don’t watch either of the stupid spinoffs.
The Simpsons - i still catch an occasional episode, but it’s not the essential viewing that it was a decade ago for me.
ER - i know it’s long gone now, but this show turned into a complete farce by the end. I stopped watching with any regularity when Mark Green (Anthony Edwards) died, and the helicopter falling on Romano (Paul McCrane) marked its descent into total stupidity.
I quit watching The Office and 30 Rock after My Names is Earl was canceled. Michael Scott ruins The Office for me and I still like 30 Rock, but I’d rather be doing something else. If Earl was still there to lead me in, I’d probably still be watching the other two.
I still watch The Office, partly out of habit and partly because my wife really likes it, but i agree with you completely. If they wrote Michael’s character out altogether, i wouldn’t be at all sorry. The only things i really find entertaining now are the minor characters: Kevin cracks me up, Meredith is great, and Creed is excellent.
I didn’t know my Name is Earl had been canceled 
I’m really surprised to see so much consensus on some shows; even more surprised that I agree.
Desparate Housewives: I recall the exact moment when I’d had enough: the tornado episode.
My Name is Earl: jail.
The Office and The Simpsons: I’m not there yet, but another couple of Simpsons episodes like the Israel one and I’m out, and too much more Scott-buffoonery and I’m gone.
My one unique deviation: Scrubs: I stopped watching because I don’t like Zach Braff, either because of his acting, or because he reminds me too much of the jerk that produces the Girls Gone Wild videos.
I stopped watching ER sometime around the time Dr. Romano had his helicopter problems.
I stopped watching Grey’s Anatomy and Boston Legal when my then-wife and I separated. I just didn’t care enough about either to keep watching.
Another X-Files dropout. It was interesting for the first couple of seasons until Teh Ebil Conspiracy story arc became the dominant theme and then it just stopped being fun to watch.
From Show Tracker, May 2009, after the cancellation:
"During a conference call with reporters today, Ben Silverman, co-chairman of NBC Entertainment and Universal Media Studios, said the network opted to cancel “Earl” and “Medium” because neither the fans nor the advertisers had waged a campaign to save them the way viewers and the Subway restaurant chain did for “Chuck.”
“If that’s how they’re running their network, good luck to them,” Garcia said." I don’t believe that for one second, but if that’s true, if that’s how they’re deciding what shows to pick up, wow."
Maybe fans would have waged a campaign if they’d known there was a chance the show would be cancelled. It was a total surprise to me, and to the show’s producers too, who got a phone call the day before the schedule was announced.
It was Heroes Season 3 for me as well. Season 2 was so blech that we really didn’t get that into it, so when season 3 opened with Hiro being a complete dork, among other wth decisions, we just slowly stopped caring when the new show was available to watch.
Battlestar Galactica lost me midway through season 2. I heard it got better again, but I just stopped caring about it.
Heroes - enough said.
24 - I finally bailed on it this year - something I should have done about four seasons ago.
My Name is Earl - I always enjoyed it when I watched it, but it was never a show I actually looked forward to. So as soon as I missed a couple of episodes, I gave up.
Boston Legal - I’m not sure why I stopped, because I still liked the show. Perhaps it was that it was getting too preachy. But it just slowly dropped out of my viewing rotation.
Reaper - Loved the show, but news of its imminent cancellation caused me to abandon the last half of the last season. I had them queued up on my DVR for months, because I kept telling myself I wanted to watch the last episodes and wrap it up. But I never did.
30 Rock is on the bubble. We still watch it and enjoy it, but I’ve got about the last five episodes queued up, and we haven’t watched them and feel no compelling need to watch them. They’re strictly in the, “Nothing on? Oh well, we could watch one of the 30 Rock episodes” category.
The Apprentice. I recently got back into it with the celebrity version, but I had lost interest for awhile beginning the season they went to L.A. The show had already lost quite a bit of steam by that point. I only watched the season opener that year and I was bored out of my mind.
24 - Watched the first season, pretty good. Watched last season, only made it halfway though. Too far-fetched, everyone is a double agent, bad guys pull off some really amazing schemes. I hear this season has problems too.
Lost - Made it through the beginning of the third season before things just got too weird for too long, and I didn’t believe the writers knew where they were going.
X-Files - Same thing as Lost, but it took until the last or 2nd to last season to reach that conclusion.
Alias - As I mentioned in another thread, Sydney got tortured too much, the Rambaldi Device was stupid, and Sark got away one too many times.
My Name is Earl - I didn’t completely stop watching, but the Earl in jail and Earl living a dream life storylines took the show from “watch every week” to “watch when I get around to it.”
Heroes. First season was brilliant, then it just stopped having any semblance of a coherent plot.
I hate to say this, but… I’m really close to giving up on House. The last episode was so weird I stopped watching it right in the middle. It doesn’t help that they’re airing one episode every several weeks.
To be fair to you, that’s when a shitload of Lost viewers quit. I didn’t, but I damned sure considered it.
Middle of season 3 was BAD.
-Joe
**Heroes. **
But then again, that was why this thread was made right?
I can’t believe you guys went past the first episode of the second season. You can’t re-arrange people and their powers in effort to get new plots. Totally didn’t buy that.
PrisonBreak Season 1 remains one of the BEST seasons of TV ever. To say that the first season was “Tight” [in terms of writing] is an under statement. Granted they could have made up Tattoos as needed, but the entire idea of a road map of episodes was crazy. To have 20 or so episodes already “Written” before the pilot. The show was perfect. It might have taken tropes heavily from 24, but it did it’s older brother one better, many times over.
Season 2 : Icing on the cake. Season 1 was great, there was no way they could do it any better. Could they? Yes. Season 2 was great, if for no other reason, because of the call-back to the digging.
Season 3: C-R-A-P I gave up on the show halfway in season 3.
Season 4: Came back to the show, and it was different, the mechanics were there, and the product might have been the same, but it had jumped and everyone, EVERYONE knew it.
24 I forget what season I dropped out on. I think Palmer the Second was in office, or soon after that.
Way too many things I couldn’t get on board with :
The US President is against the US? Yeah. No Dice.
I wanted FlashForward to be the next “Time trick” show. 24 grabbed me because of the “Real Time” idea, even if it abandoned it, and pissed all over the premise later.
FlashForward wanted to be the next time trick show, but, apparently it couldn’t keep the pace.
The Hiatus apparently was to make the show better, but, no one cares now.