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.
Complete Monster - Rhapthorne is one of the most repulsive villains in the Dragon Quest series. While the characters aren't initially aware of it, Rhapthorne is present from the beginning to the end, actively causing all the calamities in the game. His most heinous acts include turning the residents of the castle Trodain into immobile plant people, killing Marta in cold blood (after forcing her to come out by holding her son hostage), and ordering the murder of the unborn child of the Godbird Empyrea. He also did most of his work by performing Grand Theft Me, which trapped the victims of that into mental torture.
Apparently, the original versions of the game got synthesized music, whereas localizations got an orchestral soundtrack, and the theme that plays while fighting the final boss is probably the most awe inspiring orchestral you will ever listen to.
Demonic Spiders - Dead Ringers, who given enough time to summon backup can use an attack that wipes out the whole party.
Fridge Brilliance - During Marcello's ascension to the Lord High Priest, he gives a speech talking about the unfairness of birthrights, the useless nobility who trod upon others, etc... then he gets to speaking about "a Goddess who does nothing", and the player realizes that the death of Abbot Francisco, after he'd expressed confidence that the Goddess would save him, just may have hit him harder than it appears. May also count as Hidden Depths.
The Hero's immunity to curses, at least once you start to realize how it affects gameplay.
The guards of the prison island, in a world where almost everyone has a British accent, have Australian accents.
Hilarious in Hindsight - One of the random bookshelves in the game talks about phony fortunetellers, mentioning that they're mostly charlatans that use cryptic phrases and dramatic gestures to sell their act better. The book describes Kalderasha's fortunetelling completely accurately. He's also completely genuine, and 100% accurate to boot.
Les Yay - Jessica getting a Puff-Puff counts as this.
Also as a Crowning Moment of Funny - "Jessica laughs triumphantly, having won the battle of the bulges." What's even funnier is that not only is Jessica essentially immune, but that the offender loses their next turn out of shame.
Magnificent Bastard: Marcello, for a while. Despite acting mostly for petty reasons, you almost have to respect him for becoming Lord High Priest in a matter of weeks, effectively playing politics with the entire Church and winning. Not to mention resisting Rhapthorne's possession, because he's just that focused. Not even one of your party members could do that.
Moral Event Horizon - Rhapthorne was always evil, but when he murders Abbot Franscisco in cold blood...
At the very least, Francisco and the other sages' death's were needed for his plans to be fulfilled. Before he killed Marta, however, he tried to kill her son(whose death wasn't) in front of her after promising to spare his life if she did as he asked, which she did.
Gemon destroying Empyrea's unborn son with himself, which Rhapthorne is implied to have ordered if Gemon was ever defeated.
Let's not forget what Marcello pulls once he gains control of Rhapthorne's power for a while...
Nightmare Fuel - It's hard not to get chills at the cursed Castle Trodain. Or seeing Rhapthorne's true form for that matter.
Even some of the enemies can be disturbing. A Capsichum, one of the first enemies in the game, is two gigantic, anthropomorphic bell peppers, impaled together on a kebab skewer.
The cut-scene where Rhapthorne breaks free of the statue of the Goddess on Neos is rather terrifying — particularly the glowing eyes.
Rescued from the Scrappy Heap - King Trode is snobby and demanding, and comes across as a whiny, useless plot device early in the game. However, as the story progresses, it becomes clear that he is not a total buffoon, but a compassionate (if fairly egotistical) monarch who wants to preserve what little dignity he has left. He also builds (and later upgrades) the Alchemy Pot for you, which is absolutely essential for getting higher level items. And of course, there's his showing of ninja skills during one of the endings.
The Scrappy - Charmles is an intentional example. He is literally hated by everyone who encounters him except his father. Yes, that includes the main characters who are required to escort him.
Ironically, his father is quite aware his son is a severe wuss and a Jerkass, and strongly implies that he would love to see the boy man up and assume some responsibility. In either ending, King Argonia gets a Crowning Moment of Awesome for taking this to its logical conclusion.
Also, for those who have played Dragon Quest V and Dragon Quest VI, Charmles is an unsympathetic Expy of Prince Harry (V) and Prince Howard (VI). Unlike those two, who actually grew some balls and became honorable and mature, Charmles... doesn't.
Scrappy Mechanic - The "wave of ice" boss ability. It's on over half of the bosses after Dhoulmagus, and it clears every buff on your party, meaning that if you just spent the last several turns buffing up your party, raising tension, etc, those turns were just completely wasted. Not particularly dangerous, but incredibly annoying.
Tear Jerker - Late in the game, you try to rescue the legendary bird Empyrea's egg from monsters. One of them pulls a Taking You with Me after his defeat... on the egg. Empyrea's grief at losing her baby hits hard; the fact that her chick's spirit chooses to become a party power-up doesn't help the sense of guilt much...
It does, however, make his theme song that much more endearing.
Also, don't forget Angelo's backstory. While not one of the most emotional ones in the series, his father never told him that he had a half brother who was cast out of the house once Angelo was born — but Marcello at least found a good home in the Abbey where he studied hard. Unfortunately, Angelo as a very young boy came to the abbey looking for a place to call home after his father died and left him with nothing to his name sans a few possessions he could carry. Still crying from the loss of his family, the first person Angelo met in the Abbey was Marcello, who kindly said that everyone in the Abbey would be his family... until, that is, Angelo introduced himself, and Marcello instantly became a Magnificent Bastard, angrily telling him to leave and accusing him of trying to steal his life from him. Sure, Angelo wasn't exactly well-behaved in the Abbey, but if one thinks about it from his point of view....
In fact, most of the deaths that occur in the game count as this. One of the most heart-wrenching deaths is of Marta, because the English VA playing her son did such an incredible job turning a stereotypical Russian guy into a bawling, tragic mess as he weeps over her body...
That One Boss - Dhoulmagus. He has two forms — his first, where he splits into three copies of himself, and the second, where he assumes a demon form that is somehow even stronger than the combined might of the three from the previous fight.
Other bosses include Empyrea the God Bird, and Captain Crow the ghost pirate, who vastly prefers attacking when he has maximum tension. All these bosses can go twice in one turn, and can remove every single buff on your party at will.