THINGS I HAD FORGOTTEN FROM HARRY POTTER

I've decided to read more often, and so to start off I chose Harry Potter and the Sorcerers Stone. I learned somethings that (re)blew my mind.
  1. Mr. Dursley is a drill salesman.
  2. Hagrid was expelled from Hogwarts.
    Really though, I'm 26% of the way done and it's been mentioned at least twice. Say what? I always thought he was just a squib.
  3. Hedwig's name.
    According to chapter six, the name came from Harry reading A History of Magic while being shunned by the Dursleys.
  4. Dudley's tail.
    We all know he was given one by Hagrid in the cottage by the sea. But in the book (unlike the movie?), Dudley has to have it removed at a hospital, which is the reason Harry is able to get a ride to Kings Cross.
  5. Dumbledore has hobbies.
    According to his chocolate frogs card, they include chamber music and tenpin bowling.
  6. The Great Hall seating chart.
    Although the later movies make it appear that students can sit wherever they want, it's clear that Gryffindor is seated at the end table on the left.
  7. The number of staircases in Hogwarts.
    Got a guess? Anyone? 142.