Well, I think he wants a fight and is trying to goad you. I
  don't think he's nuts but he wants a battle - probably wants to
  win. Sometimes I play along with people like that. I give them a
  decent battle and then I start predicting their moves, which
  they hate and then at the very end, I give them the trophy and
  say, "You win with a superior logical argument", because the
  game *I'm* playing isn't to win an argument; it's entertainment
  and the potential to acquire new knowledge and I continue as
  long as I find it entertaining and I'm learning something..