Jerry Mouse (Gene Deitch era & The T&J Comedy Show)

Jerry Mouse is one of the two titular main protagonists (alongside Tom Cat) of the Tom and Jerry cartoons.

But during both the Gene Deitch era and the Filmation era (which follows the same footsteps as the former era), he is portrayed as extremely unlikable to the point that it's even out of character for him and has frequently been depicted as anti-heroic and even villainous, eventually going so far to become the direct main antagonist of the duo in quite a number of episodes of both eras.

Why He Was a Dirty Double-Crossin', Good for Nothin', Two-Timin' Mean-Spirited Jerkish Mouse
Note: This only applies to his incarnation in the Gene Deitch era of Tom and Jerry, as well as Filmation's The Tom and Jerry Comedy Show.

In General

 * 1) He has been flanderized beyond recognition and has lost all of the charm and likability he had in the classic era, and it wasn't until the Chuck Jones era when he finally reverted back to his original personality. He's gone from a troublesome and mischievous, yet cute and lovable mouse into a malicious and sadistic jerk who constantly tortures Tom for little-to-no reason. He is so bad to the point that it could almost already give his Famous Studios knock-off counterpart a run for his money,
 * 2) *Unlike in the classic and Chuck Jones eras, where Jerry's antagonistic tendencies towards Tom were meant to be all play rather than serious attacks while bonding with Tom over a mutual sentiment towards an unpleasant experience, here, he takes it too far by downright making Tom's owner torturing Tom for his own sick amusement while showing absolutely no mercy for Tom. Worst of all, he never gets any comeuppance for his actions (with the minor exception of Calypso Cat), which he occasionally does in the classic and Chuck Jones-eras even whenever he provokes Tom while taking it to the extreme. Most of these really show the writers had Jerry at his absolute worst and Tom being portrayed as utterly harmless.
 * 3) In most of these cartoons, he often acts more like a villain than a hero, which makes it extremely hard to root for him.
 * 4) He's extremely sadistic, as he goes so far as to laugh at Tom every time he gets into all sorts of violent abuse and misfortunes, especially from Tom's overweight abusive owner, especially when all the chaos caused is entirely the mouse's own fault.
 * 5) As the result of his flanderization, the cat-and-mouse dynamic between him and Tom in this era has been badly butchered beyond belief:
 * 6) *With the notable exception of the episode Buddies Thicker than Water, instead of being frenemies (both friends and enemies at the same time) with Tom (often due to their immense conflicts with one another), here both he and Tom are instead depicted as straight-out sworn enemies that downright hate each other while barely sharing the same bond they had with each other, with both of them being more mean-spirited and hateful towards each other than usual.
 * 7) *As mentioned before in Reason #3, he is downright malicious as during this era he's the one entirely responsible for all the conflict between him and Tom. This ultimately results to Tom posing almost no threat to him and doesn't even feel genuinely threatening at all, unlike the the classic and Chuck Jones eras.
 * 8) He usually has Tom get into trouble with Tom's owners even though it wasn't his fault, with the worst offenders being the Gene Deitch era cartoons "Down and Outing", "High Steaks" and "Sorry Safari" where he gets Tom cruelly abused by his overweight abusive owner non-stop.
 * 9) The injuries that he conflicts on Tom are more lifelike and brutal rather than being cartoonish and funny.
 * 10) His gags had gone from funny, wildly hilarious and entertaining in the classic era to mostly flat, stale, unfunny and mean-spirited in these eras.
 * 11) The laugh that he makes is very creepy as it legit sounds more like a hyena or goblin's laugh sped up than a cute mouse's laugh, thanks to his voice actors Allen Swift and Lou Schieimer.
 * 12) Like Herman from Herman and Katnip, he also qualifies as a Gary-Stu.
 * 13) Jerry isn't usually seen because of how small he is, which results in most of the characters in the era not being able to see him, Jerry uses this as his advantage when getting Tom in trouble. Not helping is the eras' bad animation and nonsensical logic (even by Tom and Jerry standards) resulting in how he manages to escape before he gets spotted by other characters being confusing and not making any sense whatsoever.
 * 14) In each short, he never gets punished. Instead, he wins in every episode of the Gene Deitch-era and the Filmation era, and with the minor exception of Calypso Cat, he never gets his comeuppance. That's making him a Karma Houdini.
 * 15) Sometimes, his design goes off-model, mainly due to the low budget of the cartoons of both the Gene Deitch era and mh:terribletvshows:The Tom and Jerry Comedy Show.
 * 16) His flanderization is one of the main reasons why both the Gene Deitch eras and the Filmation eras of Tom and Jerry are hated by critics and fans, and succeeded in turning him into one of the most hated Tom and Jerry characters of all time, to the point that some fans even started hating him as a whole for no valid reason whatsoever since then, even when he's not flanderized and is still a good character before and after those two aforementioned eras. Since then, he has created the extremely annoying misconception that Jerry is an unlikable sadist who tortures Tom solely just for fun. In other words, he gives the original Jerry Mouse a bad name.

Gene Deitch Era

 * 1) He sabotages Tom's chances of getting the affections of a female Persian cat in Calypso Cat.
 * 2) He would be flanderized again, but only worse in Filmation's The Tom and Jerry Comedy Show.

Filmation's The Tom and Jerry Comedy Show

 * 1) His flanderization returns in mh:terribletvshows:The Tom and Jerry Comedy Show, since that show seems to follow the footsteps of the Gene Deitch era. Worse still, his sadistic nature from the Gene Deitch era is shown to be even more obvious and exaggerated in that show than it is here, as evident in numerous episodes such as Heavy Booking, The Plain Baron Strikes Again, Kitty Hawk Kitty, and The Puppy Sitter.
 * 2) in numerous episodes such as Spike's Birthday, The Puppy Sitter and Say What? for example, he behaves rather mean and cruel to Spike Bulldog when the dog is supposed to be his best friend and support him. And worse, it doesn't even help that Spike in this show seems to be even more oblivious towards Jerry's cruel nature than usual, and constantly defends him from Tom for no particular reason even though Tom technically did nothing wrong to Spike to begin with.
 * 3) *Granted, Jerry may not be the greatest friend to Spike Bulldog in some episodes of the classic era and the later revivals mainly due to him duping Spike as a shield against Tom via stealing his bones, bothering his son Tyke or disturbing him just to frame Tom, these moments were few and far between and cleverly used to wrap things up in said cartoons, and not to mention, most of the time, these were mainly done out of self-defense to protect himself from Tom whom is violently chasing him. But, to have Jerry actively harm Spike for no reason out of sadism and pure malice just so that he could see Tom suffer from Spike's wrath out of self-amusement in these cartoons does makes this out of character for him.

Redeeming Qualities

 * 1) He was a much better character before the Gene Deitch era and has massively redeemed himself in future Tom and Jerry cartoons since the Chuck Jones era (though he got flanderized again only in The Tom and Jerry Comedy Show).
 * 2) His character design, despite going off-model at times, is still cute as usual.
 * 3) Buddies Thicker than Water, The Tom and Jerry Cartoon Kit and Carmen Get It! are the only cartoons which he was ever likable in this era of Tom and Jerry, as in the former, he did help Tom from freezing out in the cold, and his abuse towards Tom in that cartoon is justified because Tom betrayed his kindness by throwing him out into the cold in favor of getting pampered by his thin female owner. and in the latter two, he is just like his original counterpart.
 * 4) He does get his comeuppance in Calypso Cat as he is being pursued by Tom at the end for sabotaging his relationship with a female cat, much to the point of losing her to a calypso player.
 * 5) He's not that bad compared to Herman, his plagiarism.

Trivia

 * Itchy from Itchy & Scratchy is very likely to be loosely inspired partially by Gene Deitch's more villainous incarnation of Jerry from Tom and Jerry because of this Jerry's sadism and his cruel & manipulative tendencies towards Tom during the Gene Deitch era, as well as how the Itchy character itself as a whole is a parody of the villainous ideal of Jerry from Tom and Jerry.