Elon Musk is already a billionaire 20 times over, yet the 47-year-old tech entrepreneur spends an obscene amount of his time working. And his 120-hour work weeks have been "insanely painful," he told Kara Swisher in October.
So what drives Musk?
"The fundamental goodness of Tesla ... so like the 'why' of Tesla, the relevance, what's the point of Tesla, comes down to two things: acceleration of sustainable energy and autonomy," Musk said on the Tesla quarterly conference call on Wednesday.
Exciting to see all the new electric vehicles coming to market! We created Tesla to accelerate a sustainable future & it's happening!
"The acceleration of sustainable energy is absolutely fundamental, because this is the next potential risk for humanity," Musk said. "So obviously, that is, by far and away, the most important thing."
But autonomous cars have the potential to "save millions of lives," according to Musk, so that is also critical, he said. (Between 2035 and 2045, autonomous vehicles could save 585,000 lives "conservatively," according to a 2017 report released by Intel.)
And practically, with self-driving cars, "if you're on the road, you can spend time doing things that you enjoy instead of in terrible traffic. So it's extremely important," Musk said.
Currently, Tesla vehicles are built with the hardware necessary for self-driving capability, but they will not be able to operate autonomously until they have additional software, according to the Tesla website.
"The system is designed to be able to conduct short and long distance trips with no action required by the person in the driver's seat," the Tesla website says. "All you will need to do is get in and tell your car where to go. If you don't say anything, the car will look at your calendar and take you there as the assumed destination or just home if nothing is on the calendar.
"It is not possible to know exactly when each element of the functionality described above will be available, as this is highly dependent on local regulatory approval," the Tesla website says.