What's the secret book that you absolutely love but that you never recommend because you don't want to know if others don't like it?

What is the secret book you carry with you wherever you go, that gets you through all of the good and bad times, but that you never recommend because it would break your heart to know others don't feel the same?

Mine is the Hero and The Crown by Robin McKinley. My mom bought it for me in 3rd grade and I've read it every year since (I'm 25 now). I was being bullied in school at the time so a bullied misfit first-sola (princess) who fights dragons and whose best friend is an old horse and eventually saves the world was exactly what I needed at that time. And I've recommended it maybe once in my life because I never hear anything about it, never known others who've read it and I don't want to know that it's because they hate it.