This is not a story about ratings. This is a story about shows that have overstayed their welcome.
Shows like "Glee," "House" and "Grey's Anatomy" are still pulling in respectable ratings, but are a shadow of what they once were. For every show like "Freaks and Geeks," "Sports Night" and "Party Down" -- great shows that were canceled too soon -- there are series that risk their ultimate TV legacy by staying too late at the party. Here's why six once-terrific shows are past their prime in prime time.
The first season of the show was something new and different and fun.
The second season -- it was kind of like that kid you knew in junior high who came back from summer vacation for the first year of high school and had outgrown his awkward phase. His sudden popularity went to his head, and he became a bully who was berating Foo Fighters and Kings of Leon because they wouldn't let him play their music on his show.
And he kept relying on stunt casting like Gwyneth Paltrow and Britney Spears, shifting focus away from characters like Jane Lynch's Sue Sylvester, who, in season 1, had already secured herself a spot among the all-time great TV characters.
"Glee," by that point, had begun to drink its own Kool-Aid -- or Slushees in this instance -- and creator Ryan Murphy's media fights with rock stars were just the most public proof that the show had become too self-important.
Of course, it is important, and wonderful, to see diverse characters on TV, especially for younger viewers. But it is possible for people to not enjoy "Glee" and its many musical interludes and still support the show's point of view.
Popularity and show quality don't always go hand-in-hand, but it is worth noting that ratings are way down.
Doesn't it feel like "Gossip Girl" has been on for longer than five seasons? Yeah, that's not a good thing. Soapy dramas have to walk a fine line between too little action and piling on so much drama that the story lines and characters become tedious and unbelievable.
"GG" has hit the latter point.
Was it the Blair-Dan flirtation that sent the show hurling toward jump-the-shark status? Serena's affairs with her teacher and Nate's married cousin (and Nate himself)? The Blair and Chuck breakup and her eventual engagement to a prince? Jenny dealing drugs? Dan's novel? Yes, yes, yes, yes and yes.
'Grey's Anatomy" has had so many casting changes that we can't remember who's still on the show sometimes.
Earlier this year, series creator Shonda Rhimes tweeted the current season would "definitely not" be the series' last.
That's too bad.
And there's been so much partner-swapping, overwrought drama and McDreamy pouts over the problem of the week in his relationship with the angst-addicted Meredith that it's difficult to believe so many viewers have stuck with the show this long, its eighth season.
The Denny-Izzie brain tumor story line alone would have done some shows in -- and that was back in season 5.
He's been in jail and rehab. That's fine if you're, say, playing Iron Man. But if you're a doctor, the go-to diagnostician, this is not the resumé you want to present to your patients.
Add in the many, many cast changes, and the fact that the show has fallen into a formula of bringing Hugh Laurie's House to the brink of redemption, only to see him embrace his inner jerk once again, and the diagnosis is clear: After this, the show's eighth season, it is definitely time for "House" to be surgically removed from the Fox lineup.
The writing staff of "The Simpsons," on any given day, could probably throw away more good jokes than most comedy writing staffs could come up with in a week. Even in its 23rd season, the show is still funny.
But it's also tired. We know these characters in and out at this point, from Homer and Bart to neighbor Ned and supporting Springfieldians like Comic Book Guy and Squishee-slinging Kwik-E-Mart owner Apu. While there was a sweet spot when that familiarity allowed writers to do things with the characters that tickled fans, now it just means the show never feels fresh anymore.
And by the time "The Simpsons" hits its silver anniversary -- it was renewed earlier this year for its 24th and 25th seasons -- we're going to be longing even more for those earlier years when the show could still surprise us.
Familiarity often opens comedic possibilities for a sitcom.
But all it has done for "30 Rock" is open the door to make the characters even more outlandish, and to repeat the same jokes about them over and over. We get it -- Kenneth the Page is backward, Liz Lemon is perpetually single and career-obsessed, Tracy is crazy, Jenna is pathologically selfish, Frank is gross.
With Alec Baldwin -- who rightfully snagged lead comedy actor Emmys for what were the show's two best seasons -- continuing to say season 6 will be his last, it's time to enjoy the antics of the show, and the show-within-the-show, for one more season. And then let's send "30 Rock" off to that big cancellation heap in the sky.