When we first got this book for my 3-year-old son he didn't even really want me to finish reading it the first time. Now, at almost three-and-a-half, we've read it several times in the past few weeks and he thinks it's hilarious. He thinks it's silly but there are several times he asks 'why?' which is my queue that something is over his head. I just looked at the description and I see that it's for Age Level 6 - 8, that may explain it. This is also great news because that means he's enjoying it now and will for another several years.
As an adult, it's a fun book to read, and even more enjoyable to look at. I think they could have done such a better job of the picture on the cover. There are so many really good, fun images in the book and I don't feel the cover represents them. *SPOILER ALERT* When the animals come back to ask Tilly to be silly, the picture of them all standing in a row with the frog holding the flower is so awesome, I wish I could get a print for the wall.