When I read non-fiction it tends to be science.
I read for pleasure and for knowledge (the pleasure of knowledge being one of those pleasures
) and feel no guilt in what I read or don't read. The concept of guilt for not reading non-fiction (or classics, or "literature") is one I have some trouble grasping (though please only take this as a lacking in understanding by myself, and not at all as a criticism.
I guess to get close to understandng, at the moment I feel guilt for not reading...at all. I'm not sure why, but I guess there is a sense of letting self-enlightenment and an enjoyed pasttime go to waste. Then, I'm retired, and there are many pleasures I let go that even surpass that of reading. I guess the guilt I feel is laziness and wastefulness (and failure and self-disappointment and...well, let's leave that for the therapist to determine
)
Cheers,
Marc