Now Itachi wasn't the best teacher Kaiba could've, but atleast it wasn't Ibiki or Anko. He didn't fear them, he feared what he would do to them if they pushed his buttons. Anko had already went too far with him once, in the end she was found by Kakashi, tied to a tree and bloody from head to toes. She never bothered again after that, not that he truly minded what she usually did, it's just that this time she had went too far.