In my opinion, you know people by what kinds of things they read... Here's some of my favorite quotes from some of the  books I've read:

“That's always seemed so ridiculous to me, that people want to be around someone because they're pretty. It's like picking your breakfast cereals based on color instead of taste.” - Paper Towns

“We don't get to choose what is true. We only get to choose what we do about it.”  - Beautiful Darkness

“You have to believe it and you hate it. I don't have to and I think it's beautiful.” - Bridge To Terabithia

“Books are the ultimate Dumpees: put them down and they’ll wait for you forever; pay attention to them and they always love you back.” - An Abundance Of Katherines