These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
And not always by the players. In one MNF game at Chicago's Soldier Field, a field-goal kick went over the catching net and a fan jumped from the stands caught the ball in flight and landed cleanly on his feet.
The special Friday game on Christmas Eve in 2004. Bonus points for being a Week 16 game for the NFC North title.
Sometimes intentional, sometimes not, in the play-by-play booth. Usually provided by Don Meredith.
The cameras once focused on a fan sitting by himself during the end of a blowout game at Houston's Astrodome. When he realized the camera was on him, he gave the nation The Bird.
Meredith: "He's telling us his team is number one!"
Crowning Moment of Heartwarming: The New Orleans Saints re-open the Superdome following the horrors of Katrina with a concert from Green Day and U2, then beat up their rivals the Falcons.
A lesser known variant: In 1975, Alex Karras (filling in for the then-departed Don Meridith) quipped that Raiders lineman Otis Sistrunk was from "The University of Mars" (Sistrunk's school was listed as "U.S. Mars" which stood for "US Marines"). From then on, the Raiders' changed Sistrunk's college in ther official literature from "US Mars" or "none" to "U. of Mars".
He wasn't far off: Mars was named for the Roman god of war.
Never Live It Down: Howard Cosell's infamous referral to Redskins' receiver Alvin Garrett as "that little monkey".
Break the Haughty: The subsequent vilification this incident sparked (not helped by the fact that Cosell was rather disliked by his peers)
The Scrappy: Dennis Miller - for every fan who loved his out-there metaphors and similes, there were nine more who just wanted him to shut up.
Seinfeld Is Unfunny: Many of the standard parts of sports broadcasting - heavy use of on-screen graphics and instant replay, multiple camera angles - were innovated by MNF.