Book clubs
Peter would sign up for book clubs, but never paid any attention to their flyers or catalogs. When the month’s automatic selection arrived in the mail, he would carefully open the invoice attached to the outside to see what the book was, and if it wasn’t one he wanted, he would re-seal the invoice and return the package unopened. Eventually, the book clubs switched him to the secret alternate plan where they only send a book if you explicitly order it. I don’t think he intended any part of this to happen; I think he would just forget to tell them to cancel ahead of time.