Mo Willems was so helpful. I had met him a number of times, and I knew from his books how funny he was, of course, but it was really neat to be able to have his feedback. He's so great with comic timing. Working with him was like taking a master class in comic timing, because he could pinpoint right away if a section wasn't working. I remember him saying once, "No, you need a beat between this page and this page," and it was like, oh yeah, of course. I hadn't seen it, but being so good at what he does, Mo noticed it right away.