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: Grand Chase
Breather Level: The Wyrm's Maw / Ignis Mountains. In between the annoyance that is Ashtaroth and the evil that is the Altar of (im)Balance, Ignis looks positively easy in comparison.
It's still worthwhile to advance your job, because the Skill Trees often have passive boosts that apply to these jobs, too. Also, it's not unreasonable to assume that the second jobs onward will have Skill Trees. And in Season 4, advancing to higher jobs gives you a fixed stat bonus.
MP-recovery equipment in PVP (though this has been nerfed when Season 4 rolled around).
Critical Chance equipment and cards. Double Damage is great in PVP, but when you realize that grabs can take out well over 1/3rd of your HP normally, and some people have up to about 50% critical, it gets game breaking. Then there's the more powerful 1 MP skills, such as Arme's Level 2 Stone Curse - which WILL kill you in one critical hit.
Dio at the time of his release was a walking Game Breaker - while he did take a massive nerf, he is still absurdly versatile and powerful.
Brazilians Love Mari and Dio: A popularity event, when taken place in the Brazilian version, had Mari and Dio voted as the most popular characters in the game.
Before season 4, Zig cannot hit you with his usual attack if you are in front of him. You could easily solo hims for 6 Hero's Bullions everyday
This left a question. If they bother to fix the bug in a boss' attack, why they didn't fix the bug in The Iron Guard/Hammermon that enable him to damage player behind him using his regular front punch?
Subverted in the first stage on Phantasmic Sector. After spending minutes defeating 3 Poisonous Mushroom( on steroid), you will be ambushed by 2 level 85 Treant( for your information : the game level cap is 75)
Amy's continuous "IT HURTS" whining whenever in Fatal status also qualifies.
Jin's heavy breathing whenever in Fatal status.
"Your power is TRUUUEEEELLLLYYYY depressing." Worse if Veigas isn't on your team, cause that means you're losing mana too!
Narm: Most of Ronan's lines. "It's my victory!" is a particularly Narm-ful one. (He says it differently for his Magic Knight and Aegis Knight jobs, but both are equally as Narm-ful.)
Some of Lire's lines can also qualify. "Oh, no... I won!"
Narm Charm: The reason Ronan is particularly popular with the fanbase.
Pandering to the Base: PVP is overpromoted due to the fact that no one in the community really cares that much about dungeons.
Ronan came before Lass and Ryan due to people whining about having to play as a girl.
That One Boss: The game starts off easy, but then smacks you with quite a few of these. Each fully completed continent has at least one, besides Bermesiah: Ellia has the Giant Stone Golem, Silver Land has King Guang / Ness and Victor, and Xenia has Yamini / Juriore and Thanatos. Archaemedia and Alcubra/Atum haven't got their hard bosses... yet.
That One Miniboss: Vanessa and Ashtaroth are usually considered to be much harder than their end-of-level bosses Zen/Samsara and Bultaros/Mynos, respectively. To wit: Vanessa can corner-lock you with consecutive Spinning Phantom attacks when in Wolf form.
Iblis of the Temple of Domination is also a mind-numbingly hard miniboss in Champion Mode.
That One Level: The Altar of Balance in Season 2; the Castle of Domination in Season 3.
The Castle of Domination puts the Altar of Balance to shame, and is practically Nintendo Hard on Champion Mode.
Heroic Dungeons also qualify, unless you know the way around them.
The Temple of Cuatal / Origins also qualifies if you go through it using a solo Lire. Nearly all of the enemies there (including Vanessa and Samsara / Zen) have Arrow Defense.
And now there's The Shrine of Ruin, which despite its level requirement (40 and up) makes the Altar of Balance look like a walk in the park by comparison.
Hell's Furnace (despite the lower level requirement) can contend with The Shrine of Ruin in sheer difficulty if you come unprepared.