Some really don't imagine that other people don't treat their own possessions with any more respect than they do. I stopped lending books to two people who would break spines, dog-ear pages, and handle them with hands that weren't clean.
I've told this story before, but here it is again: When Aunt Pittypat asked to borrow my 18th-C wig and a tiara she said "I'll try to take good care of them." I said "No. You will take care of them and return them right after the event in exactly the same condition."
But since she was one of the banned borrowers of books that was the last thing I ever lent her.