I'm at the end of Terry Pratchett's books, for now, and have started reading "The Salmon of Doubt", from Douglas Adams. Under the title The Book that changed me: "The Blind Watch Maker", by Richard Dawkins.
His response to "Why did it strike you so much" is beautiful:
"It's like throwing open the doors and windows in a dark stuffy room. You realize what jumble of half-digested ideas we normally live with, particularly those of us with and arts eduction. We "sort of" understand evolution, though we secretly think there's probably a bit more to it than that. Some of us even think that there's some "sort of" god which takes care of the bits that sound a little bit improbable. Dawkins brings a flood of light and fresh air, and shows us that there is dazzling clarity to the structure of evolution that is breathtaking when we suddenly see it. And if we don't see it, then, quite literally, we don't know the first thing about who we are and where we come from."