Please name one book that you read completely, and wish you had never read it. And why, if you like.

For me, it was "Invisible Darkness" by Stephen Williams. It is about the real-life killer couple Paul Bernardo (who is still in jail, very unlikely to ever be released) and his wife at the time, Karla Homolka (who totally got away with it…the proof came after she was 'cleared'). I have read a great many [...]