I had a boss once who was so level-headed and almost textbook on what an ideal boss is supposed to be like. He had that extra something, almost like a talent to be a boss. Then seemingly over night he changed and became extremely peevish and used volatile emotions all the time to make decisions.

Oddly enough, I learned so much more from him after his transformation than when he was level-headed. Pretty much, I learned what not to do as a boss.