What do two billionaires discuss at lunch--perhaps investments, politics, hobbies? But when Sir Richard Branson met Donald Trump for the first time over lunch in Manhattan, he says they talked about revenge.

In a recent blog post, the Virgin Group founder recapped his first impression of the Republican nominee. Branson wrote Trump spent the whole time discussing how he would dedicate the rest of his life to "destroying" five people who refused to help him out of his latest bankruptcy.

"I left the lunch feeling disturbed and saddened by what I'd heard," he wrote. "For somebody who is running to be the leader of the free world to be so wrapped up in himself, rather than concerned with global issues, is very worrying." In comparison, Branson said in the same post, a past lunch with Hillary Clinton was filled with substantive talk about global conflicts, women's rights and education reform.

In a previous blog post he described Clinton as "a safe pair of hands and a leader of supreme experience and know-how." In contrast, he flatly stated that "a Donald Trump presidency would be a disaster."

Branson finds two things most disturbing about the election: A lack of policy discussion, and Trump's temperament. He wrote in the first of the two blog posts that the Republican candidate is "irrational, aggressive and he lacks informed ideas on how to grow jobs in America."

Branson is British and can't vote in the upcoming presidential election. But he wrote that his American contacts, "especially some very successful entrepreneurs," are registered Republicans. However, Trump's extreme views and lack of political knowledge has left them unable to vote for their party's candidate.