“Must-see TV” was NBC’s promotional name for its Thursday night lineup of comedies in the fall of 1993. NBC promo producer Don Holm came up with the name. However, the “must-see tv” term had been in use earlier. “Two must-see TV programs” was cited in 1976 and “Must-see TV! ‘In the Heat of the Night’ Season Premiere!” was advertised in 1989.
 
As NBC’s popularity declined, it became “must-flee TV.” “NBC’s Thursday lineup goes from ‘Must See TV’ to ‘Must Flee TV’” was a headline in the Los Angeles (CA) Times in February 2013.
 
“MSNBC: Must-agree TV” was the title of Erik Wemple’s blog at the Washington (DC) Post on August 26, 2013. Wemple and others pointed out that MSNBC programming follows a certain political agenda and that hosts and guests “must agree” to it.
   
 
Wikipedia: Must See TV
“Must See TV” is an advertising slogan used by the National Broadcasting Company (NBC) to brand its prime time blocks during the 1990s, and most often applied to the network’s Thursday night lineup, which featured such popular sitcoms/dramas series, and allowed NBC to dominate prime time ratings on Thursday nights in the 1980s and 1990s. Ratings fell in the mid-to-late 2000s, and today the night is weekly behind the competition on FOX, ABC, and CBS.
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The “Must See” slogan was created by Dan Holm, a NBC promo producer, during a NBC promo brainstorming session in June 1993 at NBC Burbank. “Must See TV” made its first appearance in NBC promotions in August 1993 and included the day of the week: “Must See TV Thursday.” In late summer of 1993, NBC wanted viewers to tune in an hour prior to Seinfeld, and created the “Must See TV” slogan to brand the comedy block. The first “Must See TV” block promo aired during late summer repeats and promoted Mad About You, Wings, and Seinfeld – Frasier had not yet premiered. It ended with the words “Get home early for Must See TV Thursday.”
 
Google News Archive
8 January 1976, Spartanburg (SC) Herald, “TV: An Electronic Revolution Will Change U.S.‘s Viewing Habits” (AP), pg. C5, col. 2:
“Betamax is for when you have two must-see TV programs,” says Shiramatsu.
(Sony spokesman Kozo Shiramatsu—ed.)
 
23 July 1978, Boston (MA) Herald, “A guide to Boston lifestyles” by Nat Segaloff, The Magazine, pg. 4, col. 1:
Must-See TV Show
(A category comparing various types—ed.)
 
11 November 1988, Boston (MA) Herald, “Epic ‘War’ is quality miniseries,” pg. 44, col. 1:
But it’s not the size of the project that makes “War and Remembrance” a must-see TV event. It’s the quality.
 
24 October 1989, The Times (Trenton, NJ), pg. B8, col. 5 ad:
Must-see TV! “In the Heat of the Night” Season Premiere!
 
Google News Archive
6 January 1990, Portsmouth (OH) Daily Times, pg. TV1, col. 3:
“Drug Wars” is must-see TV
(NBC’s “Drug Wars: The Camarena Story”—ed.)
 
26 August 1990, Fresno (CA) Bee, ‘Easy Transition to School Pace”:
What time is his must-see TV show?
 
6 June 1993, Dallas (TX) Morning News, “TV shows focus on the famous” by Ed Bark:
This is the must-see TV event of the summer, a terrifically entertaining trip through an I-me-minefield of fame and its costs.
     
26 October 1993, Miami (FL) Herald, “TV’s Great Depression,” Living, pg. 1C:
The Great Depression offers the hope that America pulled itself out once—and could do so again. It’s must-see TV.
 
Google Books
Top of the Rock:
Inside the Rise and Fall of Must See TV
By Warren Littlefield with T. R. Pearson
New York, NY: Anchor Books
2013
Pg. 235:
Warren: I would like to be able to say that the phrase “Must See TV” was the product of hard work and assiduous calculation. Not remotely the case.
 
The “Night of Bests” began in the eighties on Thursday with Cosby at 8:00, Cheers at 9:00, and Hill Street Blues at 10:00. We felt we had the potential to get that Thursday magic back.
 
John Miller: (...) Don Ohlmeyer said he wanted to label our night of appointment television on Thursday. “You guys figure out what you want to call it.” The first lineup was Mad About You, Wings, Seinfeld, and Madman of the People, L.A. Law at 10:00. That was the fall of 1993.
 
We wanted to come up with a name for this night because we wanted to package it. There was a guy who worked for us then named Dan Holm. He suggested, “How about Must See TV. It rhymes.”
 
We said, “Okay.  Let’s go with Must See TV.”
     
Los Angeles (CA) Times
NBC’s Thursday lineup goes from ‘Must See TV’ to ‘Must Flee TV’
February 26, 2013|By Meg James
Thursday was once the most profitable night of the week for NBC. But the network’s prime-time ratings and fortunes have eroded dramatically in recent years, forcing network executives to rethink their strategy.
 
Washington (DC) Post
MSNBC: Must-agree TV
By Erik Wemple, Published: August 26, 2013 at 5:29 pm
(...)
The smugness is easier to copy than the wit. MSNBC has a growing cast of anchor-bloviators — hosts like Martin Bashir, Tamron Hall and, of course, Al Sharpton, who rant and then invite like-minded guest commentators to assure them that they are right.
 
Must-agree TV, in other words.