I have not really studied Pearl Harbor much, but before today, I did not realize that many of the Japanese aviators actually felt dishonorable over having attacked without first having officially declared war on the U.S., stating that there was "no honor in attacking a sleeping enemy". There was a communications blunder by the ambassadors which prevented the war message from being transmitted to the President.
All these years, I've thought/been taught that it was intended to be a sneak attack and that it was supposedly a complete kamikaze attack, only to learn that this was not true.