"I know I'm fortunate to live an extraordinary life — I've been knighted, met the most extraordinary people and attended the most amazing events — but there's never been a point in my career in which I've felt I've 'made it,'" he wrote on LinkedIn.
This mindset could help explain Branson's wild success.
According to Richard St. John, who interviewed hundreds of highly successful people for his book "The 8 Traits Successful People Have in Common," the world's highest achievers are never complacent. They continually push themselves out of their comfort zones and are always improving, "whether it's their career, project, product or service."
Author Thomas C. Corley drew a similar conclusion after his five-year study of rich people: "In the case of self-made millionaires, they experiment with new things, new ideas and new people."
While the average person tends to find peace of mind in familiarity, rich people continuously step outside their comfort zones in order to improve, no matter how much success they've seen or wealth they've built.
"The way I see it, life is all about striving and growing," Branson said. "I never want to have made it; I want to continue making it!"