“Factories go on making safety pins, and every day people go on buying safety pins and yet, somehow, there never is a safety pin when you want one.”

Kate and Mrs. May begin their discussion of the Borrowers after noticing that a crochet hook has disappeared. By discussing the disappearance of ordinary things in such an extraordinary way, Norton attempts to inject a little magic not only into her own story but also, by extension, into the lives of her readers, who can all easily imagine that their own lost items over the years may have been filched by a different family of Borrowers.

“They thought humans were just there to do their dirty work, great slaves put there for them to use.”

 In this quotation, Arrietty tells the boy her views on why humans exist at all: to make and provide the various things that ensure the Borrowers’ survival. Because Mrs. May repeats this line to Kate verbatim, it suggests that the boy initially repeated Arrietty’s belief to his sister, thus indicating that even he had a somewhat negative view of the Borrowers’ lifestyle, which could, by human standards, be considered one revolving around theft. (The very euphemism of “borrowers” also shows the tiny family’s blithe approach to appropriating supplies that are not their own.)