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: Final Fantasy X-2
Angst? What Angst?: Gippal has considerably less angst about his past than the other three Crimson Squad members. He isn't as traumatized like the others by the events, but you can tell from his actions that there was a lesson learned. He's the only one who acknowledges Paine when he meets her - he excitedly says "you!" but plays along when she pretends they've never met.
Anticlimax Boss: Vegnagun, which can be taken down almost effortlessly if the characters' levels are above average. Then, the Final Boss is a piece of cake in comparison and has unoriginal movements.
An accessory that makes all hits do max damage when on low health, combined with the Gunner class's technique that hits an upwards of 20 or so times. What's more, this attack can be done during 1000 Needles, which lasts a good 10-20 seconds, and ensures the enemy can't attack. It's possible to string these together multiple times in a row for ridiculous amounts of damage one after the other. Yet, this is almost necessary to get through the Bonus Dungeon. There's a reason this game allows you to add an extra 9 to the damage cap. Un-broken in the International version, in which it also grants the user Auto-Berserk status, thereby preventing use of multi-hit abilities (although the Thief still gets two hits per turn, which helps).
Lady Luck's Random Reels ability, lining up three 7s using a combination of carefully timed pauses. This activates an ability called CONGRATS! which will bribe any bribeable target (including all Via Infinito bosses except Trema) and give the player gil and all of the items, gil and EXP they would normally win for winning the battle. It's a cheap and easy way to win just about any battle, hampered only by the disadvantage that it takes a long time to activate and you have to survive until it does in order to use it.
The alchemist class has free healing potions as well as mixes that make you invincible. First strike, Smooth Sailing and Adamantine can turn a songstress into a tank and her terrible agility allows her to spam her songs the entire battle.
Two Dark Knights spamming Darkness + an Alchemist spamming Mega Potions = most enemies/bosses not exclusive to the Bonus Dungeon go down like chumps. What's more is that there's an accessory called Ragnarok that (when equipped) will stop Darkness draining the Dark Knight's HP.
Rikku and Paine's Special Dresspheres (Yuna's doesn't get powerful until high levels, by which time there are probably far better options available), so much so that some players play the game without using them, much like the Aeons from the previous installment.
Also qualifying as a Disk One Nuke in international version is the Psychic dressphere. This dressphere's abilities "Excellence" or just "Magic Guard" and "Physics Guard" grants a character immunity to all magic and physical attacks, meaning that the one way to damage them is through status effects, which can be amended through a "ribbon accessory". The high AP cost to learn these skills can be amended through by the level up system level up dressphere's means that you can learn these skills first. High MP cost? No problem! the high cost for those using those skills can also be amended through the use of any of the special accessories more specifically the "Ragnarok accessory", which brings down the cost for all MP skills to 0. In other words the the character can become invincible.
Covering Oa'ka's debt early can make the player very rich, especially if you do so in Chapter One.
Creature Creator in the international and HD editions. Being able to recruit nearly every fiend out there and use them in your party instead of YRP, and every single one of them have their own small story. That's not even going into the tournament-style Fiend Arena, which gives you incredibly good items in later tournaments, and not going into fulfilling requirements needed to unlock certain fiends and tournament cups. There's just so much to do, that you can spend hours in creature creator without even progressing in the main story.
Yojimbo's Zenmato does the same thing with the added bonus of depleting all of your MP. Unlike the Magus Sisters, that attack was worse when he was on your side, but justified in that keeping it that way would've made the boss fight with him next to impossible.
That One Boss: Far too many of the bonus bosses than should be healthy.
Nooj deserves special mention. Lightfall is what you NEVER want to see hit you. Not only does it drain MP, but it hits HP pretty heavily too.
Azi Daharka, a skippable boss. His normal physical attack is several attacks done as one attack (so you can't stagger him at all) and drains your HP, while his Damocles Photon attack does 50% of your max HP. The best part is that it's Lost Forever if you don't try to encounter it in the final dungeon.
The Experiment machina at Djose with all of its stats at level five and wreck even a high level part with ease. In particular, its (mercifully rarely used) Lifeslicer does damage equal to its target's MAX hp. Unless you're use some sphere grid or accessory with Break HP Limit, whoever he uses it on WILL die.
That One Level: The Thunder Plains New Cave that's unlocked after completing the quest in Act 5. A veritable maze with non-sequential doors that rely on adding up certain numbers that are given to you throughout. Have a pen and paper with you, because you will be referring back to it, as the combinations of later doors often involve the codes from previous doors.
That One Sidequest: The matchmaking/publicity sidequests, which require you to walk up to random NPCs and pick from a list of five statements, which will prompt either a positive or negative response from the NPC. The problem is, you're given no clues whatsoever as to which statement to pick for which NPC, and if you want the best results for either sidequest (which is required for 100% Completion), you have to be near perfect. In a sidequest involving the worst kind of Trial-and-Error Gameplay imaginable. You're thus reduced to either consulting a guide, Save Scumming to oblivion or blowing all your money at the Calm Lands building up rep the slow way. Even if you DO consult a guide for it; it's a GAME-Spanning quest!
The last sidequest before the Final Boss gets as long as possible even more if you make a mistake and have to restart.
The audio drama manages to turn even Yuna into when she breaks up with Tidus out of nowhere by claiming there is somebody else she loves. Several fans have lost all of their respect for the character.
They Just Didn't Care: Most of the game's material is recycled from Final Fantasy X. Even character models that are supposed to be updated to show a pregnant Lulu uses the original one from Final Fantasy X. Most bosses were recycled too but given different levels.
They Wasted a Perfectly Good Plot: While dealing with the groups that emerged in the political fallout of the last game made for interesting final act, the game would have been a lot more interesting if that was the plot main story.
The Good and True ending came out as completely random. There was no build up or reason (except one vague line from Bahumat) to explain why Tidus revives two years after the events of Final Fantasy X and how is Shuyin's incident related with him.
Additionally, Shuyin's similarities with Tidus confused a lot of players and wondered what was their relationship. Word of God is that it is a coincidence.