What book do you feel is/was kinda overhyped?

Harry Potter. Very shallow surface level magic where nothing made sense if you thought about it.

To add to this:

Hogwarts was well thought out and imaginative. The setting was practically a character in its own right.

But Harry Potter himself was unbelievably bland. He was nothing special, but was treated as if he were because of who he was related to or otherwise connected to.
- Harry is bland because he’s the reader stand-in in the wonderful world of magic.
- to be fair that is extremely English
The best part of HP, and the bit that I think captured imaginations and has given the series any lasting appeal is just the whimsical magical world. Silly magical Britain, basically.

Even as a child and before JKR went off the deep end into transphobia, the best bits for me were the sections between leaving the non-magical world, and before the plot kicks off at Hogwarts. The actual plot itself was middling and at times forgettable. The underlying themes and their (lack of) resolution are best not thought too hard about.
- JK is a middling author who happened to hit on "silly magical Britain" as the spice that made her work popular
I mean, it's a kid's book. Maybe YA.

It has some general appeal to adults, but a book that's intended to be read by kids isn't supposed to have the same complexity as an adult fantasy epic.
Fully agree! The premise of a hidden magical society is really fun, but Rowling did a crap job of building a coherent world with what she had.

Anything by Dan Brown but especially The Da Vinci Code

I picked this one up "to see what all the fuss was about", and put it down after about 50 pages.

Enders Game

I will possibly upset a lot of people with this one but the twist in the end was obvious really early and the main character was terrible. Really shallow writing. I was honestly shocked when I realised just how popular it was.

There is so much better SF out there I still don't understand it.

Enders Game was one of my favorite books... until I turned 17 or 18.

If you didn't read it before you were eligible to learn to drive a car I'm not surprised you didn't like it.

Its a great book for middle school aged kids, for adults it's just OK.
- If you didn’t read it before you were eligible to learn to drive a car I’m not surprised you didn’t like it.
  
  You hit the nail in the head with that, I read it as a first year university student. The Heinlein juvenile novels are high art by comparison.
  
  That was my surprise when talking about it online years later, the number of adults who loved it. The ones who read it at school and were in nostalgia mode I could understand but those that read it in their 20s I could not.
Oh no, not Enders Game! I loved it… but I understand the criticism. I felt that the main character not being very likable added to the story, but that’s personal opinion.

On the Da Vinci Code, it’s a lightweight page turner, I still thought it was enjoyable, but totally forgettable.
- I felt that the main character not being very likable added to the story
  
  I should have worded that better, the characterisation of the main characters in the novel was terrible.

All GRR Martin. The writing is so dry I couldn’t get into it. Super word usage was just weird, like his insistence on “breaking the fast”, but most of it is still modern English, so this word choices stand out as sore thumbs.

After a while, it seemed to me that the white point of the books was to show how many plot twists the author could string one after the other. Still read the first four books, hoping it would get better.

Indeed! I read all of the GoT books, and they are just not good. There does not appear to be any logic to the world. The dude just keeps adding elements, never explaining how they fit in the world. Just cheap tricks and twists that are based on nothing.

I enjoy good fantasy, and magic is a part of that. But a good fantasy world usually only has a few sources of magic, and somehow they are connected to create a world that's coherent and follows its own rules. Bad books just keep randomly adding new incoherent elements whenever the author gets stuck and refuse to explain anything:

Dragons

Bunches of different and unconnected gods

Weird shadow assassin creature created by two people having sex, and some kind of intervention from one of the random gods

White walkers

Weird trees up north

Bran's magical magic of magicness

The entire plot with assassin's that change face

...

It all honestly reminds me of a book that was written and self-published by a friend of a friend. It was self-published because they couldn't find a publisher that was interested... And every two damn pages they added a new random type of magic. Martin is just better at dressing it up and selling his crap, but I think Martin and that friend of a friend have similar world building skills.

I know it's a love-it-or-hate-it type of book, but Name of the Wind. Beautiful prose. But just the most uninteresting lead characters and antagonists.

It also has quite some misogyny if you think that he is friend with the girl he “loves” just because he wants her to fall in love with him but, somehow, it’s not the right time yet. But if he keeps being there for her, she is going to fall for him! So sleazy.
When I was reading the book something was irritating me but I couldn't tell what. I finished the book and looked at other people's reviews and realised the thing that was irritating me was how the main character was perfect at everything especially how cringe it was that he could pick up a musical instrument after many years and play it so perfectly it brings people to tears.
- Yeah. The main character is just unnaturally talented at everything. Music and magic and so on. And not just talented, masterfully talented. Except then he also sometimes just makes tremendously stupid decisions for some reason? Which felt like plot contrivances to generate conflict.
  
  And on the other side, the antagonists also felt very flat to me. They are bad because they oppose the protagonist, and therefore they do bad things and are unlikable.
  
  I have heard people talk about the story being narrated by Kvothe himself, and so there are likely "liberties" taken. He does say he may exaggerate. But how much book does one have to slog through before the payoff of the unreliable narrator lands?

Twilight.

I have a particular hatred for that series because of how it was introduced to me.

I was working at my local library (during college, probably a decade or so before I became a librarian myself), when our YA librarian passed me a pre-release copy. She was like "people are saying this is going to be the next Harry Potter or something; check it out and tell me what you think."
So I went in completely blind, no preconceptions about it at all since nobody had ever heard of it at the time and I don't think the galley even had an actual blurb on it.
I spent 3/4 of the book waiting for it to be about something, and my report to her reflected that. I thought it was vapid, shallow trash with the most mind-numbing characters and ridiculous plot.

Having seen what it became... I stand by my original opinion.

Ready Player One

It was a list more than a book. It read like the author was saying "look how smart I am with all these references."
That one is generational I think. It isn't going to hit all your childhood nostalgia buttons if you weren't born by about 1985.
- I was the target audience. I got all or almost all of the references, I just thought the book was awful.

Hitchhikers.

This one hurts because I want to like it when I eventually read it maybe

Less by Andrew Sean Greer. It disguised itself as an LGBT+ novel and in fact it started out like that. But it was an “American Idiot Abroad” story in truth. Dropped it after a couple of chapters.

I liked it at the time but it was just very much forgettable. I still haven’t bothered with the sequel because I forgot what the first one was even about
Aw I really liked this one! I think it appeals to the idiot in all of us (that still needs and deserves love).

Cryptonomicon. Neal Stephenson has written interesting, compelling books - Snow Crash is fun and breezy; Anathem is among my favorite novels - but Cryptonomicon just doesn't hold my attention. Lots of smart people love it, so I always have this nagging feeling that I'm the one in the wrong here.

Completely agree. I didn’t like Snow Crash either, but Anathem is also among my favorites ever.

Where the Crawdads Sing. The main mystery was predictable, the writing was nothing special and neither were the characters. After I read it I was kinda stumped why I had been seeing it everywhere.

There's a lot of demand for things that are unoffensive and easy to digest. I just watched Gran Turismo because the audience ratings on RottenTomatoes are so high. It's...terrible. Doesn't even qualify as being cheesy good. It's just so superficial and predictable, more like watching a TV commercial than a movie. But apparently there's a segment of the population who really love that vibe

Children of Time by Adrian Tchaikovsky.

Everyone seemed to hype it up as the best sci fi ever so it might just have been the hype that did it.

I thought it was a decent book but nothing really special. It just wasn't all that interesting to me. It didn't make me want to read the sequels.

Same. I don’t really know why, but the writing style did not do it for me. I couldn’t get invested in the story nor any of the characters.

Girl with Dragon Tattoo. Read it, put it down and went huh. Didn't grab me, didn't really like anyone in the book. At the time everyone was talking about how awesome it was and I was just like, really? This book?

I'm reading the Culture series by Ian Banks and I'm not sure if I want to continue. The first two books in the series just aren't doing it for me. I'm planning to read the third and if I don't like it I'm dropping the series!

I also have mixed feelings with Banks. I really like his idea of the Culture, but some of his books are really terrible. When I read them I enjoyed The Player of Games and Use of Weapons, but I disliked a lot Consider Phlebas and had to abandon Matter after a 20%...
- I've only read consider Phlebas and The Player of Games and I haven't loved either.
  
  The ending of The Player of Games left me really unsatisfied.
  
  spoiler
  
  Surprise! The library drone was actually a weapons drone and it swoops in at the last possible minute to save the day! Chapter 3 is even called something like "Deus ex Machina". Sure the player got the drone onto the fire planet using his gaming skills but the surprise "twist" just didn't do it for me.