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.
Most of the battle themes, particularly "No Education", "A Toccata Into Blood Soaked Darkness", and "Shroud vs. Sparrow".
Considering that a lot of the soundtrack comes from Crowning Music factories like Apocalypticanote See above re:"Shroud vs. Sparrow", also known as "Path", Nightwish, and Sonata Arctica, this isn't entirely surprising.
Goddamned Bats: You will learn to hate the bats that creep around in the Gallian Church in the first arc of the game.
Demonic Spiders: During the last chapter Valkyrie has to fight several huge groups of mooks. Genre Savvy would suggest that her new powers would make this a Curb-Stomp Battle, and indeed they're barely capable of scratching her with any of their attacks, but every one of them can choose to heal almost as much damage as she can dish out in one turn at any time they feel like it, either for individuals or the whole group. Or throw up a shield that greatly reduces how much damage she can do, exacerbating the healing problem. And the group healing spell also cures all status effects. And they're flatly immune to he primary magic attacks. Basically beating them down without (or even with) an inventory item that boosts damage output is a Luck-Based Mission (and such items cannot be bought from the save fairy).
Several in later arcs. Andau's death, Rana's betrayal and Laurel getting her wings are powerful moments, but the most moving scene in the game is arguably The Rain of Fire scene, where all the races on Solest put aside centuries of conflict to help each other in the wake of the disaster. All the more sad because it doesn't last.
When Gino died! This troper was holding back tears.
Gabriella's exile from her academy after Andau turns her. She may been a bigotedbitch while human, but seeing everyone she knew and loved completely turn on her actually makes you feel sorry for her.
That One Level: Andau's Castle, A.K.A. the tutorial level, has what may be the most irritating design in any RPG, involving a long sequence of trying to find which jump from a rope won't land you on a pit. None of them are the way forward, either! This is not a good way to start your game.