Bibliophiles typically keep a list of books they would like or intend to read. This is normal. 

I'm a bit backwards. For the past sixteen years, I have kept not a list of books I want to read, but rather a running list of every book I've ever read. 

I no longer remember what started this cataloging obsession, just that in the early part of 1996 I opened a file in Word, called it "Books," and listed the 8 or so books I'd already read that year. Then I kept going. For sixteen years. Textbook, comic book, fiction, non-fiction... short of recording the nutrition label on cereal boxes, if I read it, it made the list.