Call of Duty - Nothing really needs to be said here. Everyone already knows the complaints about this series.
Half-Life - These games are so.... BORING. MY GOD I AM SO BORED. I can't even say anything else here, that's how boring these games are.
Xenoblade Chronicles (and XCX) - I'm not sure I would categorize these in the "everyone loves them" group, but my, how rabid the fanboys are. I would never say either game is bad, because they aren't. But I would never say that they are great, because they aren't. I don't love them. I don't hate them. They're just kind of "eh". But ask a Xenoblade fanboy and it's immediately "ZOMG best JRPG
evarr!!!!111Sonic the Hedgehog - Yeah, the quality of the games beyond the Genesis trilogy are questionable - good AT BEST - but everyone hails the original three as masterpieces. You know what? I don't like them very much. 3 is okay (oddly the only one of them I don't own), but man, they just really aren't good games. "Let's take bad level design and tell people they 'gotta go fast', that'll sell, right?" Well guess what? I don't wanna go fast! If you go fast, you die unless you play the game so much that you already know how to just charge through it. So you gotta go slow. But then it's boring because the levels are designed so poorly because they want you to go fast.
The Witcher - I get why people like these games so much. Really, objectively they are good games. I just don't find them enjoyable. The combat is awkward, unintuitive, and overly complex. I get how it works, and I understand how it would become easier for someone over time. But I don't find myself invested in it enough to care to try.
Pokemon - Here's where I probably get dirty looks from some of you.
I just don't like Pokemon at all. I enjoy collecting things. Obviously, since I'm posting this on a video game collecting forum. I enjoy games where you collect things. I even enjoy collecting things in games where you're not even intended to collect things (like in Final Fantasy IX, I always have at least 1 of every possible item). I do not enjoy collecting Pokemon. I guess I would if the series ever
evolved (hehe, get it?), but it's so stagnant and repetitive that I'd rather not waste my time. Especially have no interest in buying two of the same game multiple times every generation. Sorry, just don't care about it.
Monster Hunter - I just don't understand this, I guess. I tried to play one of them and after a few hours of utter boredom and confusion, I decided to sell it. Fans go on and on about how great these games are, but I really just don't see it.
Halo - These can be enjoyable multiplayer games. Mindless, sure, but fun. That's about it. Not great. Singleplayer is average at best. Pretty similar to Call of Duty in that regard.
Dark Souls - I may have to give this another shot someday, but as of now I just don't like these games. It's not because they are hard. I like hard games. But I also like it when hard games are fun.
Persona - I guess I just don't like these games because I have no interest in J-pop and waifus.
Undertale - This game is just terrible. Don't even try to justify it. It's a bad game.
No offense to anyone who likes these games, of course! What's most important about games is that you personally enjoy them. It doesn't matter what other people think about them.