I'm a librarian who loves anime, manga, and reading a wide variety of genres.
Well, it's happened. I found a work I accidentally bought three copies of. Granted, one has different cover art than the other two and isn't in great shape, but still. Three. For those who are curious, the book is Anne McCaffrey's To Ride Pegasus. If I find a fourth copy, I'm writing "Do not buy To Ride Pegasus" on the inside of my wallet.
I'm nearing the end of my book cataloging project, I think. The data is probably a mess, but everything I care about as far as "Do I have this?" and "Approximately where can I find it?" is there.