To be physically fit is just a small aspect. You can be a beautiful physical specimen, but you're empty as far as what it takes to be a person, and that shows up real fast.
The guy that I worked on 'Thriller ' was a genius and he was 20 years old, but it was like working with a gifted 10-year-old. The guy who I worked on with 'Black Or White' was crazy. Michael had gone mad.