They feel like a chore. I can't play one more than 30 minutes.
It's the fact you repeat the same thing, run forward and shoot, over and over and over. There's no diversity in the gameplay.
If FPS action was just a small element of the game, like in Deus Ex and Fallout 3, then it becomes enjoyable. In Deus Ex you are interacting with NPCs and making decisions, so you get immersed in the story. But in games like Bioshock you don't care what anyone is saying since you're just on a tour bus, shooting stuff from start to finish.
I'm asking why so many people enjoy them, cause I know there's tons who do.