We have plenty of "how-to's", but I see a distinct lack of "why-for's". It's very good to know *how* to do something, but I think it's equally important to know *why* to do something.
@Efi The personal ones, absolutely. Reading a bit about the why, which is largely philosophical or at least colored by the lens of the writer, over the logical, factual 'how', of less personal items could prove to be useful.