Bill Gates shares the single-minded attitude he used to grow Microsoft: I focused my life 'just on the one job'

When Bill Gates dropped out of college to co-found Microsoft, he wasn't thinking about becoming a billionaire or running a company that's now valued at more than $3 trillion.

Gates, then 20 years old, had a much more "boring" definition of success, he tells CNBC Make It: "Back then, it was just: Is my code really good? Does it work? And can this company show the world that these microcomputers are big?"

At the time, in 1976, computer obsessives like Gates and co-founder Paul Allen were considered "hobbyists" — yet they fervently believed that a technological revolution was imminent. "It was the magic of software. And I was willing to focus my life, in my 20s, just on software, just on the one job," says Gates.

Specifically, that job was creating high-quality software that could make the general public actually embrace the personal computer. "Our phrase was 'a personal computer on every desk and in every home,' which sounds boring today, but back then [it] was completely crazy," says Gates, referencing the mission statement he and Allen often repeated to Microsoft's early employees.

That intense focus on creating the best product possible didn't mean Gates wasn't aware that there was also money to be made — in fact, he insisted upon it from the beginning. In his famous "Open Letter to Hobbyists" in 1976, Gates wrote that users needed to pay fair prices to use software so that developers, like himself, were compensated well enough to ensure they could work on creating the new, high-quality software the industry needed to grow.

Gates' singular mindset — "It was all Microsoft, all the time in my 20s ... my view of success was very much Microsoft-centric," he says — helped push the company to the forefront of the computer age,