I find conversations in books fun because I get to hear people talk without having to participate in the conversation.
In real life I rarely understand what people are doing or saying, and why. In books--particularly favorites that I re-read, because I do re-read things a lot--I know what people are going to say and it makes sense because I can see the whole picture. A book exists as a world unto itself where I can mostly see the whole picture. I really, really like seeing the whole picture and you rarely get that in real life.
I'm also a hardcore introvert and, even when I love people, talking is exhausting. Reading books with good characters feels like authentic human contact to me without actually having to go out and have contact. :)
I would also say curiosity, or downright noseyness in my case, drives a lot of my nonfiction reading.
Where do you find most of your reading now? Still going to the library?