Me: "Wait, you WHAT?!"
Player: "I read the book."
Me: *Panics a little trying to figure out what to do, as I never expected anyone to read a large, glowing, floating book in the middle of a Genius Loci house*
In my first group, I was asked to provide pretty extensive backstories, which I did at first. And then my characters started dying. Quite a bit. I think I went through two characters in three sessions. Shortly thereafter, I kinda stopped worrying about backstories and just improved it whenever the issue came up, as my characters were either going to be killed off or the campaign would be scrapped.