I loved "We need to talk about Kevin" - although I think it would have been more interesting had they not given doubt as to whether or not he felt remorse at the end. But this was right after I read "my life with serial killers" and was totally on the 'he's a sociopath and therefore doesn't feel remorse' camp. Tilda Swinton was amazing.
I guess this intrigues me because I feel compassion and empathy for everyone. The idea of people lacking this trait is so totally chilling to me. To me a person lacking humanity (and I think people can do horrific things and still posses humanity, it all depends what is driving them fear, hate etc) is beyond chilling.