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.
Disappointing Last Level: Arguably the last two chapters, which have very little to do with the rest of the game's plot, forsaking the epic quest to cure Elaine and the intriguing history of Blood Island to give us an uninteresting LeChuck showdown. You end up walking through a half-arsed parody of Disneyland, bringing a distinct shift from the piratey atmosphere from before, and the adventure and mystery of Plunder and Blood. What's more, they're notably rushed, with a significant amount of time taken up by a long and pointless exposition scene dedicated to tying up the plots of the previous games rather than that of Curse itself.
It's not out of character, though. He does the same in Monkey 2, if not at the same length.
Ear Worm: The main theme is an in-universe example: If you ask Edward Van Helgen for a pirate story, he'll tell you about a pirate crew who went insane because they couldn't get the song out of their heads.
"A pirate I was meant to be..."
Let's see you fall off the cliff six times and not get that jingle stuck in your head...
Ensemble Darkhorse: Murray is one of the most triumphant examples of this trope. Most of the time he has in the game doesn't serve an purpose and the player doesn't even need to talk to him, but fans found his Small Name, Big Ego so utterly hilarious that returned in the next two games.
The super-secret Easter Egg where you end up under Secret-style Mêlée Dock, the same horrible music plays, and Guybrush casually comments on his own dead corpse is the worst.
LeChuck's resurrection on the pirate ship, and the pirate screaming at the sight.
The Woobie: Wally is the personification of this trope. The developers actually took out a scene from the ending of the second game where he is stranded on a raft, his monocle falls in the water, and he then falls in trying to retrieve it because they felt bad for him.