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: Pokémon Ranger
Angst? What Angst?: The Pichu from Dolce Island in the aftergame are still as cheerful as ever despite their home island being vaporized.
Man: They sure don't look like they lost their home island.
Anticlimax Boss: Giant Crobat, while definitely a cool idea, is executed in a way where it is simply not difficult especially compared to its fellow Societea bosses Ditto and Regigigas. It is a sky battle, meaning that there is no rage mode, and while the player can't use any Poke Assists, it can't break the line except through attacks. This also means that its large size actually works against it, being a bigger target to only partially circle. It also has very low health and very easy to avoid attacks (Just don't get hit by those attacks).
Complete Monster: Purple Eyes in the third game. His beating up of both Rand and Nema should give you an idea of how few moral restrictions this guy has, and he only gets worse. And then there's his goal in the last Extra Mission...
Put this into perspective: Purple Eyes is a sadistic high ranking henchman to the main villainous group who ends up unexpectedly betraying his masters and becoming the Big Bad / Final Boss, and then becoming a Misanthrope SupremeNietzsche Wannabe who wants to kill everyone alive. So yes, he is pretty much the Pokémon answer to Kefka!
A big case of YMMV, but some fans think that Purple Eyes is even worse than Ghetsis from Pokemon Black And White! Well, if you think about it, even Ghetsis wasn't deemed unsafe enough to be whisked off to a different dimension...
Mewtwo is in an ancient temple. Probably placed there by Edward, but that brings up the question of how he set up that machine in such a short time...
Game Breaker - In the second game, the steel-type assist prevents targeted Pokémon from attacking. Halfway through the game, you obtain a steel-type partner Pokémon. Do the math.
Early in the third game, you can catch a Xatu. Its assist is extremely powerful, and briefly prevents the opponent from attacking. Just put it in a corner or behind an attacking Pokémon, and you've basically won.
Goddamned Bats - Golbats and Crobats in the caves will not leave you alone. Generally, any aggressive Pokémon that is faster than you, such as Houndoom, would qualify.
Moral Event Horizon: The Societea cross this when they VAPORIZE Dolce Island! And where to begin with Purple Eyes...
Probably when he beats Rand and has Nema and Leanne kidnapped. And that is before we even see him for the first time.
Kincaid crosses it in Shadows when he leaves you, many Pokémon and several subordinates on a ship that will sink in four minutes.
Surprisingly Improved Sequel: Most people think that both the story and gameplay were improved in the second and third games; Shadows of Almia replaced the capture system with a friend meter (at the cost of some of the game's difficulty; hence the "most"), and Guardian Signs allowed the reuse of friend Pokémon over and over again under certain conditions as well as making Quests less tedious by allowing you to pick up Quests as you find them rather than taking them one at a time.
That One Boss: Drapion. Not only Drapion hits quite hard, but low on HP he turns red, spamming with gas cloud giving not much time where you can freely circle him. Additionally, the fight's preceeded by two Rhyhorn and three Stunky, and you have to do all three in a row. And this is before you get the handy Shieldon. Even these Drowzee*
As Drapion is classified as being Poison-type, therefore being weak to Psychic-type Assists.
on the ship may not be enough of help and you may need to repeat fight.
That One Sidequest: If you consider the Past missions in Guardian Signs to be one big sidequest adventure, then it's this because of how insane several of them are, especially when playing alone.