Captain Underpants and the Preposterous Plight of the Purple Potty People

The wild jokes and silly scenarios make this book so fun to read aloud. I wonder if the author envisioned kids laughing this much from the start.

The visuals really bring the story to life and make the humor pop. Are these illustrations something the author always includes in his books?

There are moments of humor that also seem to teach lessons about bravery and friendship. Do you think the humor makes the messages more memorable?