Don't feel guilty, Sagan's quantitative approach is a teribly shallow view of reading. If you feel you want to read something again it's because you expect to get something out of it - perhaps to refresh your memory, perhaps to pay more attention to the subtext of the work, perhaps to study the author's literary or rhetorical techniques. You wouldn't assume that you had learned everything about a complex musical composition or painting from single listening or viewing, why assume you've learned everything worth knowing from a single reading of a book?
The only reading I ever feel guilty about is my aversion to leaving a book unfinished. I'm pretty good at picking what to read, but about once every year or two I encounter some real stinker that is a literal waste of my time, and I feel a bit annoyed with myself for plowing through to the end even though I have long ceased to expect any literary or intellectual payoff.
The only reading I ever feel guilty about is my aversion to leaving a book unfinished. I'm pretty good at picking what to read, but about once every year or two I encounter some real stinker that is a literal waste of my time, and I feel a bit annoyed with myself for plowing through to the end even though I have long ceased to expect any literary or intellectual payoff.