I have a few that I know are pretty big ones for people, so I'll just stick to two:
First, the easy one.
Believe it or not, I don’t care for Undertale.
Kinda just this. I have a lot of problems with this game in general, particularly with its combat. I think the combat really hurts the game and what it wants to try to do with encouraging you to not genocide everything. Dealing with enemies is often very annoying without a guide, because you pretty much just have to constantly guess at what will make them go away if you want to be peaceful. Once you know though, then combat with that enemy ill be the same every time with no variation ever, which on its own wouldn't be an issue, but having to go through a series of menus and dialogue options just to work on getting an enemy to leave you alone sure is just annoying. Coupled with how annoying (and occasionally actually unfair) some of the enemy combinations are when avoiding their attacks in the bullet hell portion of combat, and you just get a made me groan any time I found a random encounter. Doing the opposite and killing everything is, quite frankly, much simpler, less annoying, and more fun, but the problem is that since the game wants you to get attached to everything in it, it also wants to make you feel bad for playing that way and treat you like a monster the whole time. And if you choose to go all the way and really commit to that playthrough, then you're forever tainted now (unless you edit your steam files). The only saving graces in this game are a small, small handful of its characters and the music.
My second opinion though I know is the hotter take, but I need to stress this before I say anything else, I absolutely think this game is a good game. I just don't personally enjoy it.
I don't like Chrono Trigger. It's actually really close to something I could find myself enjoying, but every time I found something I liked, it got balanced by something I didn't (outside of its plot and characters, which I have no gripes with and think are good). I think the combat is way too easy for how interesting it could be. Characters having group attacks is awesome, but when the majority of them hit specific angles in a game where none of your characters can move mid-combat, it makes me wish it was real-time instead of turn based so I could actually take advantage of it. I think partially to compensate, a lot of the best moves hit everything on screen so positioning doesn't matter, but then those are often the best moves to use, and you end up with the usual "just spam your strongest move" problem that a lot of games have. I think battles transitioning smoothly from interacting with enemies in the world is neat, but why do so many of them have to be psychic and force encounters that you otherwise perfectly avoided? At that point why not just have random battles where the enemies come in from off-screen or something? The time travel is a neat aspect of the game, but I really don't like that there's just not much that's done with it in the side content, at least, not in a substantial way. I think overall the best way to really describe what I mean is, I just find the game kinda... tedious, I think would be the right word.