After thinking things through a bit, I agree - none of the acts in the movie are horribly disturbing in a visceral sense(at least not compared to some of the scenes mentioned in this thread...). The concept, however, really gets to you once you start to think about it... (this sort of applies to Ravenous, too, come to think about it).

Yeah, we agree...

I always found the ending to the original Texas Chainsaw Massacre (you know, where they have caught the girl and prepare to kill her) to be deeply disturbing...