Signs in Our World

Two nights in a row, my son has asked me to read "Signs in Our World" by DK Publishing. Notice that there is no author. It is not that kind of book.
My son opens this book and points to a color photograph of a street sign and says, "What this sign say, mommy?" and I say, "No U-turn" or "Truck Route" or "Kangaroo Crossing." If I try to point to signs, my hand is gently brushed away and my son says, "No, I do that." There is a strict protocol for reading this kind of book. He points, I name.
Reading this kind of book bores me silly. I have no chance for dramatic reading or funny accents, because nothing happens and there are no characters. Because I am bored, my mind wanders to thoughts like, "Why does my son like this boring book? Is this a sign of Asperger's syndrome? But if he had that, wouldn't he be smarter?" and of course these are not helpful thoughts to have so soon before my own bedtime. I don't need to lie back and fret more than I would anyway.
But of course the reason I let the kids pick their own bedtime stories is so they can pick the books they are interested in. Sometimes those aren't the same ones that I am interested in, because my kids are not me. And I don't want them to be me, or just like me. I just want them to learn to read so they can get through these boring books without me.