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.
Mandras in Fables, having projectiles, sleep, and a respectable amount of HP on top of being rather common enemies. Dragons trade sleep for slow, and can also recover their own status afflictions, but are mainly limited to the deeper floors of the "Guardian" dungeons.
Komegas in 2 are an almost literal example. Robot spiders that can shoot through you and hit your partner and are very strong...if you're not up to fighting Bonus BossOmega, you'll have to get through all of these and pray Omega doesn't show.
Fridge Horror: In CD 2, killing an enemy by kicking a bottle at them nets you a bottle of red liquid, that enemy's 'essence'. Did...did the cute birdie just bottle up his victim's blood?
Goddamned Bats: Lamias in the second game love to confuse you then smack you silly. Vampires can reduce your maximum HP, sometimes permanently.
Coeurls in Fables get two actions per turn and have specials to inflict Silence and Halt. Elementals take minimal damage from most attacks, but aren't particularly deadly themselves. Both can be terrors in the "1 HP only" dungeons, though.
Narm: Somehow, all the big threats and monologuing antagonists become considerably less impressive when you factor in that they're talking to a chocobo.
For example, the speech that the Phoenix boss gives before you fight it is instantly ruined on the first word by saying "Chocobo!..", and then it instantly becomes ridiculous, especially since some human characters at the start of the game are unsure if he can even understand spoken English at first.
The voice acting in Fables.
Nightmare Fuel: The Grim Reaper as the shopkeeper. Especially when a weaker (though still strong) version of him appeared in RANDOM TREASURE CHESTS!
Paranoia Fuel: In the second game, the Grim Reaper can appear in random treasure chests.
In Fables,Claire is among the worst of these. With ranged enemies, enemies that can easily outrun and overtake you, elementals that always take at least two hits to defeat, and monster houses all over the place that throw all of them at you at once (often impossible to avoid, if the staircase appears in the center of it all), there's no room for error. Even if you play a perfect game, enemy placement can put you into all sorts of unwinnable situations.