I've had a couple of close friends and relatives have health issues that almost killed them. Afterwords their personality changed. They became much more negative and harder to be around. The things I have read about Jobs is that he is a health nut. To have the problems he has had might have been a big emotional blow for him.

Since he has come back, things have gotten much worse for partner relations and there is almost a continual barrage of news about Apple jerking someone around. I really think they could do better with a new CEO.