While many of these are fine choices (I am haunted by the end of Dexter S4 still…), I’m going to go lighthearted and simple with my favorite episode of my favorite show: Friends - The One With the Embroys… aka “Miss Chanandler Bong.”
Fawlty Towers- Basil the Rat
ER Love’s Labor Lost. Mark Greene deals with a minor complaint from a pregnant woman, and things go downhill quickly.
Google.
Andy Griffith Mr. McBeevee
and the previously mentioned…
Mary Tyler Moore Chuckles The Clown
Fawlty Towers Basil the Rat
I’M A BUSY MAN. I have no time to waste when I want to waste time!
I was trying to think of the best episode of the Fargo series, and came to the conclusion that the entire second season (with Jesse Plemmons, Kirsten Dunst and a brilliant cast) is the answer.
Got me. 
The Rockford Files: White on White and Nearly Perfect
Well, if you have any taste at all, you already have the DVDs.
The aforementioned episode of The Outer Limits – “Demon with a Glass Hand”
The Twilight Zone – “Nightmare at 20,000 Feet”
Kraft Suspense Theater – “Once Upon a Savage Night” (later released theatrically as Nightmare in Chicago)
Dragnet 1967 – “The LSD Story”
Star Trek: TOS – “Elaan of Troyius”
Batman – “While Gotham City Burns”/”The Bookworm Turns”
The Prisoner - “Fallout”
Night Gallery – “The Caterpillar”
Star Trek: TNG – “Conspiracy”
Possibly episodes of Monty Python’s Flying Circus, Mighty Mouse: The New Adventures, The Venture Brothers and* Adventure Time*
Time’s Arrow from Bojack Horseman is amazing, as is Free Churro.
Other favorites:
GLOW: Nothing Shattered
Stranger Things: The Body
Andy Griffith: The Haunted House
Dark Shadows: Episode 211, The Arrival of Barnabas Collins
Inspector Morse: The Way through the Woods
Twin Peaks the Return: pt 8
Gilligan’s Island: Seer Gilligan
Columbo: Now You See Him
Amos ‘n’ Andy, toss-up between “The Kingfish Adopts Andy” and “The Kingfish Gives Andy Flying Lessons.” Throw in “The Kingfish Gets Drafted” for good measure.
How can anybody not like this show? :dubious: 
“Elaan of Troyius”? Really?!? :dubious: :smack:
Seemed like my favorite episodes of Columbo all came around the same time: “Now You See Him,” “Candidate for a Crime,” “Negative Reaction,” “Troubled Waters,” “An Exercise in Fatality,” “Playback,” “Forgotten Lady”… :o
Night Gallery has been mentioned but my favorite episode of that is “A Question of Fear”. (In which Leslie Nielson and Fritz Weaver star). And I also found the Columbo ep “A Friend in Deed” quite memorable if for no other reason than Columbo goes up against an utterly ruthless killer, who happens to be a high-ranking police official in a position to hamstring his investigation.
I was going to mention this one, just because of Roddy McDowell’s performance and the luscious Francine York as Miss Limpit, the quintessential slutty librarian. :o
My personal favorites are “Many Happy Returns” and “The Chimes of Big Ben.”
Really.
Dude, according to you, one of the “Greatest Episodes of Television Ever” is from Gilligan’s Island. IMO, such a claim throws an unflattering light on your aesthetic judgments of the medium in question.
Do you have a favorite episode of Hogan’s Heroes you would also like to mention?
ETA: And then you post your comments about big Rod. How am I supposed to assess your aesthetic judgment now? Somewhere between wise and less than wise, I guess.
Probably the one where the Germans bring barrels of heavy water into Stalag 13. Or maybe the one with the stolen French art treasures.
Don’t knock GI! It has great sociological value as a microcosm of 1960s white American society, along with some great one-liners. Not to mention Ginger and Mary Ann. :o
Sorry, you lost me here. Gene Roddenberry? 