On Thursday, Elon Musk and Richard Branson sat down for a Hangout video chat with Google for Entrepreneurs to talk about the struggles and satisfaction of starting a business. The hourlong talk, which can be seen in full on YouTube, covered a broad range of topics, such as why Silicon Valley attracts talent, and the danger of "burning out" by not delegating enough responsibility to others. Musk even hyped up the Hyperloop — a proposed train system that could travel from Los Angeles to San Francisco in 30 minutes, and that Musk won't be building himself — stating that he'd share "the full details" of his idea on Monday.

One thing Musk was willing to share today was the fact that the two companies he's currently running, Tesla and Space X, both almost went bankrupt in 2008 due to failed rocket launches and a US financial crisis that later grew into a recession. Branson, who is the chairman of the 400-company Virgin Group, said "I knew Elon in those days and I'm surprised his hair is still black and not grey." Later, he added that "there's a very thin dividing line between success and failure. And all that matters when you're building a company is survival." A key tip the two shared for any entrepreneurs: listen and look for advice. "You should seek negative feedback, particularly from friends," Musk said. "Friends don't want to tell you exactly what's wrong, because they don't want to hurt your feelings, but they often know."