As far as
KnK goes, what disturbed me the most wasn't much the setting, but the characters: i noticed that i dislike when the characters got a partially/totally fake body, or when they lose arms/legs and don't make a big deal out of it because they can replace them like it was nothing. That's the reason why i didn't like
C3 (that blonde girl was losing some piece every fight, the main "heroine" was some sort of disgrace summoning iron maidens all around, and the childhood friend wasn't human but a sword),
Ghost in the shell (that woman is 100% cyborg, the sexy factor goes to a value of -2),
KnK (I don't know how much of that girl is fake, but it looks like it's a common issue to cut her own arm in the everyday life)
In
Asura cryin i didn't like that Shuri was all machined, but on the other side i liked her character. Really, the only downside was that she was 80% metal.
In
Dance in the vampire bund i was a little disappointed that the main protagonist had lost an arm, but when i got to know that he just grows a new one because he's a beast, i wasn't that mad.
In
lunar legend Tsukihime, Arcueid gets ripped in many pieces at the beginning, but she's a vampire and can reconstruct herself (no mecha parts, just natural). This destroyed any occasion for me to feel worry for her, because even tho
In
high school of the dead I always feared that those hotties could get harmed. Fortunately their shining bouncing tits are all ok ;D
I just can't bear any kind of mutilation and other mad stuff in a romance anime. I can easily bear them in other kind of animes (I actually NEED mutilation and ripping off in some kind of animes like Yu Yu Hakusho, Ken, Berserk & co), but not when romance is involved.