Concentration/YMMV


 * Adaptation Displacement: Those who fondly recall the original see the Narz/Trebek versions as altered aberrations, while those who grew up on the Narz/Trebek shows see the original as dull and stodgy.
 * Memetic Mutation: "Not a match, the board goes back."
 * Replacement Scrappy: Ed McMahon, who replaced Bob Clayton in March 1969 at NBC's insistence, was ousted after six months because he apparently couldn't grasp the format. Norm Blumenthal says the real reason for McMahon's removal was ratings, which took a nosedive when Clayton was replaced and came back when he was reinstated.
 * That said, as a photo here demonstrates, McMahon seemed to have good memories of the show — he posed with fellow Concentration hosts Jack Narz and Alex Trebek (plus a Steve Ryan rebus) to help celebrate fifty years of game shows.
 * Retroactive Recognition: Actor/stand-up comedian Brian Haley appeared on a few episodes of Classic about two years before his big break on The Tonight Show. After that he appeared in a number of movies and TV shows, perhaps most notably becoming the Suspiciously Similar Substitute of Thomas Haden Church's "Lowell" on NBC's Wings.
 * Surprisingly Improved Sequel: The 1985 pilot and Classic Concentration used a computer-generated board with 25 panels, which was not prone to the same mechanical failure as the old board...although a glitch was eventually discovered in 1991; see Throw It In on this show's main page.
 * They Changed It Now It Sucks:
 * The Narz era added "Extra Number", which when matched allowed the contestant to pick three numbers on the next turn (for the final season, picking three numbers became regular gameplay), and "Free Look" automatically exposed that part of the puzzle. In addition, the main-game prizes were formerly the parting gifts given during the tail end of the original series.
 * The 1985 pilots with Orson Bean (there were five taped that day) had contestants matching related words in the main game, with $100 per match. Considering how words can connect in myriad (and sometimes obscure) ways, using predetermined "connections" was a Standards & Practices nightmare waiting to happen (imagine a contestant, after being told the two chosen words were not related, who immediately proceeds to give a sound, logical connection between said words right on-camera; what do you do?).
 * Classic returned to prize matching, but had an absurd amount of rule changes. One of these, forcing contestants to retire after winning a car, caused a What an Idiot moment near the end.
 * What an Idiot:
 * Lots of misguesses, such as "The Pounds You Lost Tonight" (1974) and "Polly-Wolly Tear Doll" (1978). The correct answers were "" and "", respectively; for the latter, Narz explained that.
 * Orson Bean. For some reason, he felt an absolute need to read out each prize's name during the 1985 Bonus Round.
 * Ben's moment of stupidity on the fifth-to-last episode of Classic.