We skipped over one of the most crucial deaths in the movie, Hyman Roth. Since Roth and Michael's relationship throughout the movie was always based on business, you would think that Roth's death would be business as well... but I don't think that's the case.

Michael said "Roth thinks he'll live forever," and whether or not Roth was playing up his sickness, Roth was getting old and wasn't going to live much longer. Plus, he was sought by the law when he returned to the U.S. and probably would have lived the rest of his life in prison or under some kind of supervised program. At that point he wasn't really a threat to Michael. But Michael goes to the length of sending one of his guys on a suicide mission to kill Roth. That's pretty personal to me. I think there is nary an ounce of business present in that killing.

We could spend another 3 pages worth of discussion on whether sending Rocco on the suicide mission was business or personal so I will leave that alone.