Aside from Musicals, every single episode that features “guest stars” from another show, like when Kramer showed up on Mad About You. The Law & Order episode featuring the cast from Homicide was another awful example.
Seinfeld: The episode where Kramer gets Elaine’s friend pregnant and screams “She’s laaaaate!!” out the window. Something was off that whole episode.
WKRP: The one where Venus gets set up by a look-alike hood. Really preachy and strange.
The Shield: The one where they go back to “Day 1” - weakest episode in a great show.
ER: I couldn’t even bear to watch the episode with Sally Field doing her “crazy” act. I think it made me stop watching the show it was so bad.
Keep in mind that I haven’t seen that brilliant series since it originally aired but I think you missed the point here. I actually remember this and it was a great moment. In their previous encounter, the sherriff punched Ferrer’s character and the character explained how he was non-violent in the Ghandi model and that he really loved the sherriff. I recall reading that that was supposed to be the end of Ferrer’s character but that the reaction was so positive that they brought him back.
I rewatched the entire series over a week a couple of months ago, and it stuck out like a sore thumb. Mind you, my chronology is pretty hazy too, those later, post laura episodes sucked on a fairly huge level. (Ted Raimi is killed an turned into a giant chess piece WTF?)
That would be “Let That Be Your Last Battlefield.” Yep, it stunk. So did The Omega Glory, Spock’s Brain, The Way to Eden (the hippie episode). And Bread and Circuses has to be an all-time low in an impressive string of them.
For STTNG, I’m voting for Skin of Evil and/or the one where Wesley was going to be executed by the Californians. Oh, wait, that one where the Traveller told him he was special is a good contender too.
X-files, I gave up before the last season, but the ones that stick out in my memory as being truly bad were the one from Cancer Man’s point of view (was that First Person Shooter?) and Home, which I know a lot of people liked but I thought it reeked.
Married With Fishsticks on Xena. As bad as the title is, the episode is even worse. How that piece of amphibian excrement made it to the screen is utterly baffling. I looked at it dumbfounded, unable to believe my eyes.
It’s probably the only Xena episode I didn’t like.