I collect the things people use as bookmarks in library books. It doesn't happen often, but I keep what I find. Usually people use whatever is lying around, business cards and such, but sometimes they leave "to do" lists with things crossed of like "Get bible" and "resume for corn detassling" (from when I got out Generation X). These are my treasures.

I just wish that everyone wrote their name on a sign-out card, like they used to, so I could know the name of the person who needed to "Call Mom" so desperately that they underlined it four times.

Because of this, I never make sure I've removed my bookmarks from library books.

(I'm also the type to look at dropped pieces of paper to see if they're secret love(d) notes or "to do" lists that say nothing but "Drink Martinis...all day". They never are.)