Ruin a TV Show by Changing One Letter

[Defiant]

UR ( a show about emergency healthcare in ancient Sumeria)

[Kraken]

Well, I haven't seen the show, but I imagine you could ruin Dear John if you changed the Dear John letter that serves as the basis for the show into junk mail.

(Am I doing this right? )

If the goal is to befuddle me, you hit it out of the park.

[Isgrimnur]

Sliders Spiders
Strange Duck
X-Tiles - a competitive Scrabble show
The Adventures of Crisco County Jr.
Xenu, Warrior Princess
Mung Fu

[Isgrimnur]

CHoPs
Cheeks
Brasier
Thunderbards
Doctor Why
The Cosby Shot

[Kraken]

...and Dr. Why wins the thread.

[Isgrimnur]

[Sudy]

Mortal Wombat: Annihilation

Delight in this PBS Nature special in which a colony of the Outback's cuddliest marsupials slowly but inevitably dies off due to the effects of poaching and global warming.

[Sudy]

On a serious note, I never realized wombats are so large!

[dbt1949]

I thought that was capybara. Then I realized that only Australians have that kind of smile. (the wombat not the girl)

[Sudy]

Capybaras are definitely equally ridiculous.

[LawBeefaroni]

Chicago V.D.

Chicago Tire

[Lassr]

The Dick Man Dyke Show.
Hole Improvement
The F-Team
The Pukes Of Hazzard
Have Bun - Will Travel
Fappy Days

[Aliasbuck]

W - a show starring Marc Singer about an alien president (actually, that would explain a lot...)

Spoiler:

https://www.imdb.com/title/tt0085106/