There are few things as personal and intimate as reading. Reading can define us in a way, as a sort of cultural mirror that reflects our preferences, but at the same time, how we read books varies from person to person, and that in itself makes it personal. I think this has never been truer than a translation course I took in college where in addition to studying the different ideas of how to translate texts (ranging from transliteration to transcription to transposing words and sentences around for your expected audience) everyone was required to bring in a few small passages of whatever language you'd studied, translate it, and have the entire class review it. The review wasn't intended to determine the "best fit" translation (after all, there are valid arguments for and against how you should translate), but it was more of a review of how you implimented the ideas of translation.
Anyway, the piece I translated was "The Handsomest Drowned Man in the World." When I read, I usually visualize the story in my mind. By doing this, I effectively and unwittingly manipulated the story to my culture, preferences, and beliefs. The seaside in the story became a bleak Outer Banks with dunes and sea oats. The man's hands that were described as being like "oxen of the sea" gave no clue to me as to the cultural meaning behind the phrase (I've never seen a buey del mar, so I don't know how large they are, what they look like, the texture of their shells) apart from just having large hands. This text that I translated was slowly molded to something that I was familiar with, mostly because I didn't know the the cultural implications on word choice and the setting in the original text, but the same thing was true for each student in the course. Each and every person had a different, and yet personal way of translating their text.
The same is true for books that you read. The different types, plots, and characters you encounter in the different books you read have different importance for different people, either by people relating to some aspect of the book and thoroughly enjoying it or by thinking the book is a complete waste of ink and trees and wholly abhorring it. How often have you asked someone what their favorite books were, in part to get an idea of what book you want to read next, but also to get a better understanding of that person's personality? And how often have you read a book for inspiration or solely for enjoyment?