I used to be an angry man myself. I’m a recovering assaholic so I could recognize that in Steve. (quoting Jean-Louis Gassée) - Walter Isaacson

The unified field theory that ties together Jobs personality and products begins with his most salient trait: his intensity. His silences could be as searing as his rants; he had taught himself to stare without blinking. Sometimes this intensity was charming, in a geeky way, such as when he was explaining the profundity of Bob Dylan's music or why whatever product he was unveiling at that moment was the most amazing thing that Apple had ever made. At other times it could be terrifying, such as when he was fulminating about Google or Microsoft ripping of Apple.

Atop the brochure McKenna put a maxim, often attributed to Leonardo da Vinci, that would become the defining precept of Jobs’s design philosophy: “Simplicity is the ultimate sophistication.

if you can't keep him interested, that's your fault.