Nothing has really disturbed or offended me at all in the world of cinema. Probably because I'm not that easily offended nor disturbed, but also because I pretty much know what I'm expecting to see/hear when I watch a film. When you start to watch a gory or sick film, I'm pretty much physically and mentally prepared to see almost anything. Detachment from the realism, tends to find me more curious about how the shocking scenes were shot, and how the effects were created rather than the events themselves.
As for
A Serbian Film, the over-hype, rather than the 'shocking' content left me with a sour taste in my mouth. What I thought about it, you may of already read, but is posted
here.
As for sickness value, I pretty much agree with mbv on
Mordum being one of the sickest films that I've seen.