Brief Interviews with Hideous Men by David Foster Wallace
I think this is the most impacting book I've ever read.
What it is: a group of stories related only in that they all deal with relationships. Each one is devastating.
This guy seems to be able to pinpoint all of the interesting, substantial stuff, both exciting and horrible, that's hidden underneath all the shallow expectations and words we (I?) typically rely on to talk about how and why people care about each other. The effect is devastating in two ways: (1) it explodes low resolution understanding, and can even kindle entire new understandings. It's hard to think of tragedy as avoidable or absolute afterwards. And (2) in doing this exploding it reveals this terribly complex reality that, after you've seen it, you no longer have the option to ignore. The question then, of whether you can handle the new world, is left open. The answer is not obvious.