I'm hoping that Amos isn't explained/justified in some way, I really want him to be a bit of a whack job just because he is a bit of a whack job, not because event x or y happened in his past. Havent read the books so not sure if he ends up being justified by some past but I'm hoping it doesn't happen.
I've commented on this previously as i'm quite ahead on the books and can answer further in spoilers if you like without actually giving anything spoilery away.