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.
YMMV: The Infinite Loops
Common to all Loop series:
Adaptational Heroism: Some characters that were villainous in the baseline has mellowed out since they have started Looping.
Adaptational Villainy: Likewise, some characters that were heroic in the baseline have been broken by the Loops.
Broken Base: Naturally, how powerful certain characters are in regards to other characters, although arguably even worse in the loop setting due to how crazy powerful all the characters become eventually. Even when characters are powered down thanks to certain loops, there's still a heafty amount of debate over whether the characters could still easily handle it due to being genre savvy and such.
There's also the overuse of certain settings in the loops and plotlines common to the loops and settings. An example being Equestria being the dedicated 'heal all problems' loop for nearly all the loopers. Some think it's good because they're use to it by this point, and the most experienced with it. Others don't like it because the 'healing a loopers personal problems from their baseline' plot has been over done to the point of cliché for some, and others feel it wastes good character development potential for the characters of said loop because they couldn't over come it without outside help, and it often only takes one loop for the Equestria loopers to pull it off.
Chaotic Good: The Equestrian Loopers strive for a Neutral Good outlook through their enforcement of their Sanctuary Loop declaration, but the pranking and other shenanigans — not to mention having Discord among their looping population — tend to nudge them toward the Chaotic side.
The Jojo Loopers appear to be of the Chaotic Good alignment as well. Besides pulling a few pranks to keep themselves amused, they still act more or less like the heroes they were.
Neutral Good: Phoenix Wright, on the other hand, is the same as ever. Considering how much of a cosmic Chew Toy he was during the baseline, this shouldn't be too surprising.
In fact, it's possible that the entire setting has reached this level, with some of the writers for it insisting that the only thing that can hurt Stands in the entire multiverse are things that one must get from the Jojoverse, meaning that anybody who doesn't learn such tricks are going to have trouble regardless of how powerful they are.
Mutually Fictional: Not always the case, but often. The more forward thinking Loopers tend to collect large stashes of fiction from many different loops, so that they are as certain as possible to have an effective "guidebook" to wherever they end up next. Some even carry copies of their own stories to give out during fused loops.
Revealed in the MLP Loops to be deliberate — since there is only one Yggdrasil system in the multiverse, a full independent system backup is not possible as they have only one server cluster to store the multiverse on. So as a partial solution they use a RAID-esque data striping technique, deliberately caching information about each Loop in redundant chunks spread out as background data amongst other Loops. Or: Fiction exists about the setting of Loop A as books/movies/etc. available to be read in Loop B because that's how the backup archive of Loop A manifests when its copied over into Loop B's assigned partition as inactive files. Not every Loop contains fiction about every other Loop, though, with the exception of the "Hub Loop" (our own real world), the master backup archive, which has an in-setting fictional work of some kind for every existing Loop.
Uncanny Valley: Loopers sometimes regard nonloopers as disturbingly static versions of their friends and family. So far, Phoenix Wright and the eight Joestars are the only exceptions.
Nightmare Fuel: Implications of the premise aside, the loopers themselves manage to be this as well. They've become so powerful, and yet so bored. So they think of creative ways to pass the time. However, the Time Abyss has resulted in them loosing most of their morals and misgivings. They are no longer the characters we know and love; they are half-insane, unkillable, unpunishable hedonists with severe PTSD.
In general, the male loopers prank each other or people who've annoyed them in ways that would be considered dangerous at best, deadly at worst. The female loopers frequently rape or gang rape the male loopers and non looping characters. And nobody ever stops them, because nobody can.
However this is, as befitting the page, very YMMV. A lot of the sex stuff is either meant for jokes or, as was revealed in the original Fanfiction Forum threads, for Development of characters. In general Innortal tends to steer away from the sex jokes in later loops.
As befits his style of writing, any time a woman shows up to jump Ranma is played for laughs. The pranking is usually inflicted between the original five loopers themselves.
The MLP Loops:
Crack Pairing: Berry Punch and Discord have started dating in recent loops. Also an ironic development, given that she originally turned him down (while they were both Awake) in loop 44.9.
Flanderization: Candace got hit with this hard for the longest while, to the point where most of the time she only appeared whenever someone mentioned they were in a relationship with someone, but not married yet. 'WE MUST FIX THIS!' Was practically her catch phrase for the longest time. Thankfully, once the readers started to point out how this was more or less the only thing Candace was used for, the FiM writers caught on and started to bring her more in line with her canon characterization.
Trixie also got hit with this pretty hard too. Early loops had her as her usual showmare persona, albeit toned down and nowhere near as arrogant, and possessing an interest in pyrotechnics to further increase the awe factor of her shows. Now a days, when she isn't being used with Chrysalis (sometimes even when she is), she mostly appears when a massive explosion has happened (and is usualy the cause), implies she caused the previous loop crash from a massive explosion, or just in general raves about explosions to a near obsessive level.
Heartwarming In Hindsight: In chapter 8, Twilight Sparkle expresses the opinion that Diamond Tiara will only ever be a bad example. Many Loops later, Diamond starts Looping, proving Twilight wrong in all the best ways.
Hilarious in Hindsight: The first time that Discord and Berry talked she said she not even will consider date him, sixty or so chapters later they are.
An early chapter has the cast re-enacting the defeat of G1 Tirek. Flash-forward several dozen Loops, and the Running Gag about Tirek totalling Twilight's library on a constant basis.
Looping Sunset's personality is nearly identical to how she acts in Rainbow Rocks, making this Heartwarming In Hindsight as well.
To clarify: Sunset was activated as a Looper prior to the reveal that Rainbow Rocks even existed. All of her Character Development in the Loops was made without that in mind.
My Real Daddy: Some consider Saphroneth to be this to the loops format.
It got to the point where Twilight was going to name a world she made after him, but he cut that out due to embarrassment. And fourth wall breakage.
What an Idiot: A non-looping Blueblood attempted a palace coup against a more-or-less united front of Celestia, Luna, Discord, Cadance, Chrysalis, Sombra, Princess Twilight, Shining Armor (ascended to Alicorn), and Spike (as an advanced great wyrm Emperor of the Dragons). Would have been Too Dumb to Live, except he survives because they don't think he's worth the minimal effort to curb-stomp.
Twilight Sparkle (literally ROFL): You just tried to assassinate eight deities and a Greater Dragon!
Blueblood (armed only with a knife): Errr... parlay?
The Woobie: Chrysalis, once she becomes a Looper. Her first loop was "Slavequestria", where she and a non-Awake Shining Armor were Happily Married and helping runaways as part of La Résistance. Then the loop reset, and she was horrified to find that all the terrible things she did in canon were notAll Just a Dream, as well as heartbroken that the Shining she had loved no longer exists, with the Awake Shining Happily Married to Cadence. She's left horribly depressed for many loops afterwards, and even though she's now in a steady relationship with Awake Trixie, it's clear she still misses her version of Shining.
Magnificent Bastard: Haseo seems to be shaping up into one of these, with the amount of time he has spent with Shiroe in Log Horizon Fused Loops. Most noticeably is that he used the things he learned from such experiences to gain enough influence in CC Corp to throw Sakaki out of the job he blackmailed them for without very much difficulty at all.
Mega Man Loops:
Complete Monster: Waltz. Dear God, Waltz. And what's worse, due to a loophole, she's Looping. She sees nothing wrong with murder and destruction, and at one point screams she wants to destroy everything, just because. And she's got all of Roll's skills.
Nightmare Fuel: The setup for the Megaman Loops. Their universes are so fractured and fragmented by whatever broke Yggdrasil (it's implied that the Megaverse was closest to 'ground zero', and was thus hit the hardest) that the first four loop attempts shown (over 25) broke down, with the last attempt to make Protoman an anchor collapsing in under 10 seconds. And as already shown by the My Little Pony loops, it gets worse before it gets better...
The Crash, and how it started. In a desperate attempt to save the badly damaged Mega Man Loop, the admin begins a merged loop. Things start off strangely enough, with no sign of the bad doctor, but all the robots being labelled "model-letter", leading to Models X and Z, implied to be X and Zero, who utterly destroy several Robot Masters before going down. Then Model V (Vile) shows up. Blues manages to help his brother and sister take him down, everything works out fine... and then Blues is knocked out, and when he wakes up, he, Rock, Roll and the Unknown Looper are tied up as part of a strange machine. Then something apparently possessing Doctor Wily shows up, announcing that it's going to use them to escape the Loops and become even more powerful. Worse, Blues has encountered this thing before (it killed him in one of his failed Loops, posing as Doctor Light), and realizes that whatever it is, it's not supposed to exist. Then it begins the procedure. Something goes wrong, and the machine zaps Wily. The last think that Blues can recall before everything breaks is reality itself screaming...
Nightmare Fuel: The beginning of the Fire Emblem loops is this as well. Robin is the anchor, meaning that everything he remembers, Grima does too. Needless to say, Grima gets creative fast, Chrom and Lucina wake up to truly horrible loops, and Robin is trapped in his own mind for ages, watching his friends get tortured and killed over and over again. This setup ends after one chapter, thankfully.
However, this setup is followed by chapter 2, where attempts to stabilize the Fire Emblem loops repeatedly fail due to an unknown factor royally screwing everything up. The major contributor to the problem, Time Travel (ironically enough) is universally despised by every observer, who are doing their best to stop the Fire Emblem universe from looping. They are, unfortunately, Well Intentioned Extremists who will do what they think is necessary to achieve this goal...which means attempting to railroad and outright neuter as much of the random factor Robin brings into the equation. This comes to a head when it's discovered that Morgan, merely by existing, is the one responsible for the looping, and the higher-ups keep rewriting everything in order to ensure Morgan, as we know them, never comes to be, including manipulating Robin's code to the point that they set up an entirely new baseline where Robin is female and married to Chrom. Even the universe's administrators are disgusted by the "solution"note This is described as "morally repugnant"—in short, a Moral Even Horizon. Thankfully, thanks to Robin being a hugeDeterminator who firmly believes in Screw Destinyand one of the higher-ups acting as a Spanner in the Works, the universe begins to destabilize again, and are finally allowed to loop, thus beginning the Fire Emblem loops proper in Chapter 3.
Dio Brando's introduction snip in The Grand Battle of Pelennor. It's heavily implied that he fed all the members of Xcution to his zombie minions except Ginjo and Riruka, sexually assaulted her while her now mind-controlled leader and friend watched, began feeding on her blood, before throwing her body to a Zombie-fied Haku and Zabuza for them to devour. Made even worse when you realize that the Zombies now have a slavish devotion to Dio, so Haku and Zabuza can't really stop themselves from doing the horrible act.
The second Fused Mega Man / Sonic Loop, specifically the part where Sally and Sonic discuss Loops where they were roboticized, especially Sally's. Her friends start vanishing, one-by-one, replaced by insanely dangerous robot duplicates who remorselessly chase you everywhere, leaving her nowhere to run. And finally, Metal Sonic, the one behind all this, who has a truly disturbed attraction to her, captures Sally, and prepares to transfer her mind to a robot duplicate of her. He flips the switch... and the Loop ends. His machine outright killed Sally.
What Do You Mean, It Wasn't Made on Drugs?: Averted. Apparently the loop that Anakin, as Darth Vader, held a 'The View' esc talk show was caused by his coolant being spiked with something while the Emperor was experimenting with 'dark mushrooms'
This being in universe, out of universe it hard to say if there are any loops written on drugs
Considering a few of the comments by various authors in the forums, it would seem a few were written on at least lack of sleep.