There's a book that I knew I had to get rid of as soon as I'd finished reading it... to keep it around would have been to tempt my OCD beyond any rational limit.
I would swear that I gave away my copy of
House of Leaves, but there it is sitting by my bed. I usually trust my memory, and people who know me know that it's pretty solid, as long as I'm not trying to remember someone's name. Unless I'm drunk, then I can remember just about anything, but when I'm sober again I tend to have a looser understanding of that period, itself.
Even that doesn't tend to leave me with fabricated memories; what the hell happened?