This book is not boring. It, is, however, confusing. But not boring. I am not sure kids will get all of what is going on in The Boring Book: (Children’s Book about 
Boredom, Funny Kids Picture Book, Early Elementary School Story Book), but they will enjoy making their own story to the illustrations and the illustrations themselves.
Shinsuke Yoshitake’s book is another on the 2019 New York Times/New York Public Library Best Illustrated Children’s Books list. And, while they are interesting illustrations (brightly colored, busy without being overwhelming) I am not exactly a huge fan of them. There is nothing wrong with them, but I am not finding them cozy or pleasant. They are actually not boring due to color, but the action is not necessarily there and that makes them if not boring, less than exciting. However, the description in the article describes the illustrations as a “deceptively simple drawing style” and the judges liked the “Charles Schulz-like gift for droll visual pacing.” I am not sure I agree, but it is an interesting thought to mull over.
Like so many books, this means it is a book each one of us will like and dislike on our own level. Following a kid through his boring day is not boring, as he learns and asks questions about “what is boring” but the theme gets old somewhat quickly. A smarty-pants twist ending will make the savvy reader chuckle, but anyone under say, age 5, probably will not get it. Or maybe it is just an adult joke tossed in to keep the adult reader engaged.