Zombie fiction. It's just the most idiotic, self-indulgent fantasy scenario, taking place in a world where trained soldiers fail to contain a less effective fighting force than a rabble of medieval peasants armed with pitchforks, but somehow random Joe American fights and survives, justifying his (and probably the writer's) insistence on keeping a ton of guns in their house. Yeah, sure, dude, people are wrong to say you're useless, you'd definitely be more useful than those super-fit people with extensive training if, against all laws of biology, dead things started walking around and somehow didn't decompose to the point that they'd no longer be able to see or move in the space of like three days as the blood all pooled in their legs, their neurons stopped firing and their eyes turned to goo. In real life you could survive a zombie plague by staying in your house for like a week. Also it gives a really convenient reason for the "heroes" to run around killing very human-like things without any moral difficulty because they're not alive and have no feelings! Convenient! And in addition to being incredibly silly, it's not even nice to look at! Oh and then this utterly braindead genre has the gall to say it's a social commentary on how people are like zombies? Zombie fiction needs to stop throwing rocks inside that flimsy glass house it lives in.
Isekai........kind of. See, I like the concept of "person from our world is in a Fantasy world", it's been a concept I've loved since I was a kid. The problem is that modern "isekai" has become painfully formulaic and lazy. The self-indulgent wish fulfilment aspect is so over-done, the protagonist just gets ridiculously overpowered and is amazing at everything because they just happen to have the perfect skillset for that world. Every hot person fawns over them even though they're kinda boring personality-wise. The world always runs on JRPG/MMO logic even when it doesn't make sense for it to do so. Geez, at least do something interesting with the world they get sucked into? Actually maybe think about the rammifications in an economic or socio-political sense of how a world where people level up or different areas have increasingly powerful monsters or huge amounts of gold can be earned by farming "dungeons" that consistently restock with monsters? That'd be kind of cool! MMO economics is actually studied in academia, after all! But no... it's usually some loser with no hobbies outside of gaming from our world gets hit by a truck and now he's in a world that works like an RPG and he's amazing at it and becomes the strongest ever and a bunch of hot girls are into him. OR there' an "exciting twist!" where the character is... a villain! or has a slightly odd but effective character build or way of getting powerful! ...wow....so inventive...