Grey's Anatomy. It should've ended a long time ago.

Literally every season of American Horror Story (apart from Hotel which was bad from the start)

The Walking Dead

Glee, AHS, Supernatural, Arrow, The Flash, and Dexter ()

Gossip Girl

I don't think I've seen a show decline in quality as rapidly as Dexter did. Like, for the first 4 seasons, it was the best show on TV. And then 5 started and it just got stale and awful, especially Season 6, which was virtually unwatchable Also, AHS comes to mind.

Glee

Empire, Hannibal

PLL

Empire
How I Met Your Mother
Pretty Little Liars
Glee
90210
Scream Queens - oh wait.

Glee was amazing from seasons 1-3 and then became trash onwards.
AHS as well. Coven was the last decent season

AHS. Asylum was the best, and then after that it dwindled. I don't know if I can carry on watching Hotel

!!!

Just thinking about the last 'season' makes me cringe.

Charmed got really bad with time, too.

It is still a great show, that's why it is still successful after 12 years

This

The Office, American Idol, Big Brother US, Glee, Scandal.

Is this the Ryan Murphy base?

I didn't mention when it got bad tho.

How I Met Your Mother