Since Freeman himself noted that "Corduroy's world is a plotless world," we don't want to read too much into this simple book. You won't find a five-page breakdown analyzing why Freeman chose a creepy clown and a soulless bunny as Corduroy's shelfmates, but we do see some symbolism in Corduroy's quest for his missing button.
The journey begins after Lisa's mother comments that Corduroy doesn't look new because he's missing a button on his overalls. Rather than blasting some T-Swift and shaking off the haters, Corduroy immediately starts planning a search-and-rescue. Even adults can relate to his determination to fix a perceived flaw, whether they bounce between diet plans or spend way too long choosing a Snapchat filter that hides their least favorite facial feature.
Of course, in the end Lisa accepts Corduroy exactly as he is.
On a deeper level, Corduroy's missing button symbolizes self-acceptance and shows young readers that you don't need to be perfect to be loved.