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.
Canon Sue: The Grey Spy in Spy vs. Spy would always win whenever she appeared. In those strips, the Black and White Spies would fall in love with her, and out of respect for women, she had to beat both of them, but eventually, Aragones himself thought the concept was falling into this Trope, and she was Put on a Bus. (She did appear later after other artists took over the strip.)
Critical Research Failure: Occasionally in the parodies, such as failing to notice that Mystique replaced the dead Senator Kelly in the first X-Men movie.
In the Back To The Future Part II parody "Bleak For The Future, Part II," "Mutty" complains "Look at me in 2015! I'm a complete failure! Why don't I do something about that?" Probably because in the actual movie Marty a) has no idea how he turns out in 2015 and b) never does find out, although his girlfriend Jennifer does (she's in no position to tell him either, because she spends a lot of Part II and almost all of Part III unconscious).
In the "Mork and Mindy" parody, Darth Vader (who, beneath his armor, is a human) is shown as one of the aliens complaining about Mork.
Crosses the Line Twice: "You Can Never Win With a Bigot", which makes fun of bigots' contradictory prejudices. Has a family of new German immigrants moved in? They'll just sponge off of welfare. Wait, isn't one of them an electrical engineer? He's taking jobs away from the natural-born American citizens!
In Mad's "20 Dumbest People, Events, and Things" for 2008, Amy Winehouse's destructive behavior was listed at number 11. The end of the entry stated: "It makes us wonder if her next full-house appearance will be at a funeral home." Well, MAD, as of 2011, you got your wish.
Growing the Beard: Arguably, the transition from comic book to full-fledged magazine, which allowed for a wide variety of non-comic parodies.
YMMV. The original Mad comic has some of the greatest comic book storytelling ever. Even Alan Moore thinks so.
Hilarious in Hindsight: This parody ad for Cadillac back in 1960, showing a woman wearing an emblem of the car like a necklace to show off her status symbol. Who knew rappers would adopt the same style decades later?
Memetic Mutation: Alfred E. Neuman is a rare pre-Internet example; his image, known as the "What, me worry?" Kid, appeared as graffiti as early as the 1920s and in several unlikely places in post-WW1 Austria. Mad just named him and chose him as their mascot.
The mysterious gap-toothed smiling kid has been traced in advertisements going as far back as the 1890s… and it's still uncertain if the original image has been found.
Moment Of Awesome: During a company-wide vacation to the Dominican Republic, Bill Gaines discovered that there was only one subscriber in the entire country, and his subscription was going to expire that month. The entire Mad staff - artists, writers, editors, and Gaines himself piled into a bus and drove out to his house. Gaines knocked on the subscriber's door, and with the entire staff of the magazine looking on, presented him with a renewal notice.
Basil Wolverton's hideously pock-marked, hairy, blemished women. His son, Monte, carries on in the same tradition.
Tom Bunk is fond of Basil Wolverton-esque women, as well as gags relying on blood, guts, puke, snot, pus, eyeballs, et cetera. His art is at its grossest when Michael Gallagher handles the script; strangely, most of Michael Gallagher's work with other artists is very tame.
Al Jaffee loves grossout gags as well, although he hasn't done very many of late. He still has an affinity for grossly overweight women, though.
Spy vs. Spy has become considerably more visceral since Peter Kuper took over.
Refuge in Audacity: The "You Can Never Win With A Bigot" feature, in which it's noted that bigots will respond to stereotypes being refuted by changing to others, stands out, as the writers admit in the Mad About the Seventies collection that they could never do that today.
Seasonal Rot: After briefly being reduced to a quarterly issue (but then brought back to a bi-monthly process shortly after).
Other events that led to MAD magazines Seasonal Rot include: when the comic went from black and white to color, when William Gaines died, when the magazine was adapted to MADtv (the FOX sketch show that was set up as a rival to Saturday Night Live, not the Cartoon Network one made after the FOX version got canceled), and when the magazine started accepting advertisements and "sold out." See They Changed It, Now It Sucks below
Shallow Parody: See the page for examples, some of which are based off early drafts, and others involve getting things wrong or not doing the research.
We're Still Relevant, Dammit: Completely averted, as the whole point of the magazine is to make fun of anything that's new and popular, though some fans of the older issues will claim that the magazine writers are doing this to try and be hip and current.
YMMV tropes related to the TV series (the Cartoon Network one, not the FOX one):
Don't Explain the Joke: A criticism of the show, sometimes the sketches have to point out what their parodying since they figure most of the audiences (being kids) won't get it. It kills the pacing the sketches and makes some of them rather groan worthy rather then just letting the jokes present themselves.
Ear Worm: The theme song, which is just kazoo music and some guy making music with his mouth and "singing", "Hey yabba boy yamma, MAD!"
"Funny Aneurysm" Moment: The How I Met Your Mother parody "How I Met Your Mummy" ends with Werewolf!Ted taking so long to finish his story, the titular mummy walks in to tell the kids how they met. How I Met Your Mother was in season 7 when this sketch aired, but the series finale eventually revealed why Future Ted's wife didn't do something similar: She died six years before Ted decided to tell their kids the story of how they met.
Geek Bonus: "Gaming's Next Top Princess" shows that they are very definitely One of Us (or, at the very least, actually did research on female characters in video games). They even got Samus Aran's birthplace right!
The "And That's What Superfriends Are For" sketch features countless B-list & C-list DC characters.
And for actual Genius Bonus points, in the episode with "Undercover Claus", the sketch with the boy who got a time machine has him knock out the boy who becomes his dad with a "Titor" aluminum bat. It sounds like an example of Brand X, unless you remember the guy who posted on various internet forums under the name John Titor - who claimed to be a time traveler from the future.
Growing the Beard: Maybe, with more features from the magazine and a new look for Spy vs. Spy. Also with less use of gross-out humor and more variety in their sketches.
Hilarious in Hindsight: "Dr.Mouse", as a sketch, may or may not have originated as a parody - namely, a 2009 storyline◊ on Topolino, that is, the Italian Mickey Mouse magazine parodying the House TV series. Which, in turn, got its inspiration from a commercial, still from Italy, which celebrated the fact TV network Mediaset would start airing both franchises. Hell, even the cover you can see on the first link alludes to that commercial.
The skit about the ride of Paul Revere became funnier when Tea Partier Michelle Bachmann mangled revolutionary history on live TV.
The "Les the Miz / The Lex Factor" Episode had a segment called "Real Life Heroes" where a guy shoots down the antenna broadcasting Whitney. A little over two weeks later, Whitney was cancelled. Looks like his plan worked!
Ho Yay: Happens between Edward and Jacob. For instance, one skit had them discover that they turned themselves into vampire-werewolves from biting each other. They walk off like best buds and leave Bella alone in the woods.
Internet Backdraft: "ThunderLOLcats" sparked tons of complaints from viewers who firmly believe that Internet jokes should not be used on TV.
Missed Moment of Awesome: The Once Upon a Toon sketch which celebrated CN's 20th anniversary. They got the models right but for some baffling reason didn't get any of the original (or at the least current) VAs to reprise their roles given that this show is a collaboration between CN and Warner Bros, meaning they weren't in danger of copyrighting.
Nausea Fuel: The two adaptations of Tom Bunk/Michael Gallagaher back cover gags from the magazine: the first involves a boy who deflates and spews goo and guts all over the place after popping a zit, and the second, a fat woman who says that her kids "eat like a bird" — which she then demonstrates by vomiting up worms into their mouths.
Nightmare Fuel: The mini-sketch about the guy trying to pop his zit — which pops, and floods the room with his pus. And organs. And eventually his skeleton. That's right, that dude just died on camera in the most horrifying way possible. And before you ask, yes, he screamed.
Beauty Tips with Megan Fox. And not just the scene where Megan Fox turns out to be a cyborg, but her overall appearance makes her look like she crawled from the deepest trenches of the Uncanny Valley. The photo cut-out head and cartoon lips and eyebrows look really bizarre.
Doesn't help that HAL from 2001: A Space Odyssey is in her circuits.
In Fantastic Megan Fox, Megan really is a fox [which causes Fridge Logic] — one who steals Kristin Stewart's long brown hair, Scarlet Johanssen's beautiful brea—er, uh eyeballs, and Angelina Jolie's full, pouty lips just so she can be the next big female screen star.
The models they use to show live action or CGI characters can sometimes invoke this, along with Uncanny Valley.
There's the music video parody of Katy Perry's "Firework" video (called "Flammable" by Katy Putty). Much like the actual song, the parody song does have lyrics that speak out and give hope to those who are often ostracized or feel like they're not special and need to look to their inner light and let it out. The parody (like most good parodies) takes this a bit too far with the fireworks causing the clay man, the stock paper woman, and the puppet man to catch fire. While the puppet is just singed [he is saved by a man with a fire extinguisher. He is shown running around on fire at the very end though.], the stock paper woman is screaming as most of her is now blackened ash, and the clay man's head melts and falls off his neck as Katy Putty [who inexplicably survives] is carted off by a police officer for arson and murder — but not jaywalking.
The Cars parody with Lightning McQueen being crushed. For anyone who actually likes the movie Cars, this may be too depressing. For those who have either never seen the movie, hated it, or loved it, but have a sick sense of humor, this is hilarious.
"This has been a nightmare brought to you by MAD."
Older Than They Think: A sketch show based on MAD magazine's parodies, cartoons, and random doodles is nothing new (besides MADtv [which had the TV and movie parodies and the cartoons on occasion, but the doodles were phased out after season three], there exists an unsold pilot/TV Special of a MAD-based sketch show in the 1970s that included parodies of Columbo and The Godfather; the pilot was never picked up and made into a series)
Shallow Parody: Most of the time this is averted (See Above) Naru210 is an example. The writers apparently only saw the first three episodes of Naruto. "Why do all these Naruto fights happen off-screen?" The relationship between the Genin, which is similar to a group of high school students' interacting, is also skimmed over.