Alignment of incentives. I'm sure the personal humiliation of being yelled at by Jobs was a reasonably strong incentive, but I'm certain the perception that failing to deliver would have him personally sending you to the dole queue asap was even more of a strong incentive.
Compare to most corporations where the only thing you can do to get fired is fail at office politics and failure to deliver/delivering the lowest quality crap that can be passed off is just business as usual.
Alas, human don't come fully customisable. You get to pick from the packages on offer. And it seemed like for Apple Steve Jobs' good parts only came as part of a package that also included his bad parts.