The author who called this "a Haneke film in prose" is absolutely correct. "The Dinner" is incredibly interesting, cerebral and unsettling and I love it for those exact reasons. 
 Yes, the characters are completely terrible, reprehensible, morally bankrupt people (other than Serge, who is merely awful). Sadly, there really are completely terrible, reprehensible, morally bankrupt people with which we share our Earth. I've read other reviews which indicate that others found "The Dinner" to be unrealistic - unrealistic that these events could occur and unrealistic that the teenagers' act would be discussed in a public restaurant. I don't find it unrealistic at all - people do terrible things and, often, the best place to hide things is in plain sight. Even still, if you find the precise premise - two couples discussing a terrible act during a dinner - to be farcical - it still doesn't take away from the wry humor and the nausea inducing coldness of the characters. Perhaps it makes it even better! It's fascinating to watch the events of the novel play out and to gain more understanding of the minds of these incredibly warped individuals -- particularly the narrator. 
 The narrator, Paul, is infinitely readable and infinitely sickening, though I think I have a stronger distaste for his wife, Claire. And yes, there is no personal realizations here, there's no personal responsibility, no remorse, no soul searching and really, no real fear. That's one of the things that makes the book so interesting - people like this exist. They are here and they are our friends, classmates, colleagues and neighbors. 
 'The Dinner" reminds me of Haneke's film "Funny Games" - another story in which you sit through unspeakable evil, with the hope you'll be rewarded with the perpetrators getting their comeuppance. "The Dinner" denies you that satisfying, socially-promised ending just as "Funny Games" does. Yes, there's not a satisfying conclusion -- but really, is there ever?