Where's Spot? Replaced

As librarians, we try so hard to get our children to love certain books, and yet the beloved character-based books always rise to the top. Our replacement order of Where's Spot? arrived yesterday via Amazon and was greeted with lots of enthusiasm. We were using our hands to cover the animals where flaps once were glued, and then Levi caught on and would cover the animals using his hands.

Now we are back to a fully intact Spot. Of all our titles, why is Spot the most popular?