It's probably a number of things, and a passion for what you're trying to do is certainly one of them. Oftentimes these folks have experienced a problem firsthand and they're consumed with solving it. And they refuse to quit.
A lot of the great founders and entrepreneurs I've worked with are micromanaging, detail-oriented, paranoid people. They want to know everything, and they care about everything. Interestingly, most of my companies have a key executive who never graduated from college, and probably two of my six CEOs never went to college. And the CTO at another company, the star at that company, did not go to college.
See the rest of the interview with Larry Cheng on What Makes a Great Entrepreneur.