cheating, netori/ntr, incest, or anything that's taboo in-universe; by that i mean it has adverse reactions/consequences from other characters and not just roll over when you do something deplorable.
You may not agree but this is extremely rare to find in these games because most people get off...
I absolutely hate it. I play these games usually for the story, in the same manner as reading a choose-your-own-adventure. So when games make me do these nonsensical grinds, it just gets in the way of the story with no meaningful payoff.