There’s nothing in the world that says as much about you as your favorite Harry Potter book. Not your Zodiac sign, not your Myers-Briggs personality type, not whether or not you pour your milk before your cereal. (If you pour you milk before your cereal, you’re a psychopath.)
Whenever I am on a date, I ask “What’s your favorite Harry Potter book?” because that tells me everything I need to know. I know the preferred Harry Potter book of everyone in my life, and I am able to categorize accordingly. So that you, too, may walk this earth armed with knowledge, here is everything I know to be true of a person based on nothing more than which Potter tome they would save in a fire.