I found Purity, which revolves around people who have variously relegated themselves to the fringes of society, immensely alienating.

This book delivers a great strike against the notion that the idealist is an exceptional individual, someone more enlightened, more autonomous, more principled than the droning masses, by showing how self-deluding and reactive the uptake of countercultural values can be.

Many people (including me) try not to believe in that level of determinism because it's frankly very depressing. I finished the book feeling nauseated. Not a comment on its quality. Truth hurts! I liked the style of the prose and on its face it is an interesting story about interesting people. I will definitely pick up Franzen again.