Information retention after reading non-fiction

After reading a non-fiction book, do you beat yourself up over not remembering all that much? This is especially painful if the book took years to complete (e.g. Anne Applebaum's "Gulag").

It's a bit ridiculous to expect to become an Encyclopedia after reading something in passing too, though.

I feel as if working with a computer and using the internet daily destroyed my attention span, which is why I'm self concious about this.