I will also preface that I don't "hate" these games, hate is reserved for actually bad games. Most games brought up in this thread aren't even bad games, but I definitely have my issues with these.
Super Mario Galaxy - I was such a huge fan of Super Mario 64, still one of my favorite Mario games, and while I didn't like Super Mario Sunshine a ton, I didn't like Super Mario Galaxy much at all. The change to space and little planetoids, the cut back of the hub world, and add in motion control, which is a problem in most every motion controlled game, and I just don't like it. Super Mario Galaxy 2 took it to the next level and I think is the downturn of the 3D Mario games. All I hear is that Super Mario Galaxy 2 is a work of art and 3D Super Mario World is the best Mario has ever been, but I don't want that game. I don't want a rehashed Super Mario 3. They already did that in the rehashed New Super Mario Bros games. Now there isn't even much difference between them other than one being in 2D and another being in 3D. Again, not bad games, but I don't like the direction they took. The 3D games should be a more separate experience form the classic 2D ones.
The Witcher 2 - Tons of people rave about this action RPG. I find it clumsy. It's got some alright ideas, but the controls are unintuitive, the UI is clunky, it just doesn't work for me. I made it about half way through the game and then just got bored. I tried again recently and didn't make it out of the prologue. I am still interested in The Witcher 3, I love an open world action RPG, so if they can improve it, I'll be happy. I want to like the series cause it has a cool developer lol
Half-Life 2 - I never got the hype with this game. I beat it, I thought it was okay, but others made it out to be the second coming of FPS gaming. Even saying things like Ravenholm is gaming landmark for a horror-like area. No. I could probably come up with a dozen other games with areas more terrifying than that place. It's a competent shooter, very bare bones, the gravity gun is cool, I'll give them that, but I think the story is actually pretty boring. The setting and concept is cool, but I never found it that engaging. I played all there was for it and I'll play Half-Life 3 when ever they decide to actually release the game (Come on, it's been seven years since episode 2 was released. They could've released Half-Life 3 and 4 in that time frame), but I don't think there's anything really special with it.
Monster Hunter - While I wouldn't call this one "universally loved", it has it's very rabid and devoted fanbase. I don't see why it still does. I tried playing it once a long while back on the PS2. I wanted to like it cause of this idea of fighting large monsters with big huge swords and everything kinda had a weight to it, but looking at the games now, I have to wonder why people are so hooked to it still. I guess it's the same as Pokemon, in that they don't care that the game has basically been the same since it started, they just want more. I played the Wii U version recently and it felt like I was playing a PS2 game. I don't feel like it's been updated since then. A lot of the UI element and such is rather clunky and dated too. Maybe I'm abit wrong about that part, but that kind of stuff can be an instant turn off if it isn't handled well and I still feel it hasn't changed me since it's early days. It's why I'm excited for Xenoblade Chronicles X. It honestly feels like much of the same style of game, but will have RPG elements and a cool scifi setting. Seems better to me.
I have a couple more I might add later on if I feel like thinking about them lol