As I was reading, I was trying to figure out why this book seemed more enjoyable than the previous six. What I determined was that in this volume, Smith made his characters a bit more human than earlier.
Our protagonist - Mmmmmma Ramotswe - is more worried about her weight. Rra Polopetsi makes a fairly severe and devastating error. Mma Makutski and her shoes! So, even though this volume once again creates situations that are never life-threatening (well, okay, that snake) or life-ruining, and you never have to worry about a sudden shift into crazy or scary, you get a little bit more than usual anyway. Our characters are more loveable than ever because of their revealed foibles.
Plus, Smith will never give us a book that doesn't heap praise upon Botswana. I find that refreshing, and never dull.