Billionaire buddies Warren Buffett and Bill Gates held court at a Q&A hosted at Columbia Business School Friday.

The event was moderated by journalist Charlie Rose. With more than 30,000 people viewing via Facebook (FB) Live, the pair discussed everything from Trump's America to the importance of loving your job.

On following your dreams...

Buffett's investing expertise has won him the title of the Oracle of Omaha -- his hometown -- and when asked whether he'd pick a different career path if he had to do it all over, Buffett gave a firm, "No."

"I've had fun in my 20s, my 30s, now I'm 86, and I'm having fun," he said. "I'd do the same thing...Don't say you're just marking time until you get older. I've told people that's like saving up sex for your old age. It is not a good idea."

Buffett left the Columbia students with this piece of advice: "Take the job that you would take if you didn't need a job."

On vaccines...

President Trump raised fears that his administration will stoke anti-vaccination myths when he met with Robert Kennedy -- a known vaccination skeptic.

Microsoft co-founder Gates, who invests heavily in philanthropic health care efforts, vowed to stand up against efforts to hinder vaccinations.

"I'm a little surprised we have to stick up for them...But particularly in today's media, the rumors can get out ahead of the facts," he said, adding that research has shown that the benefits of vaccination are "unequivocal."

Buffett added that he admires the Gates' dedication to encouraging vaccination.

"When Melinda [Gates] is in Africa and she's holding a little baby, she is actually thinking, 'This kid needs to be vaccinated,'" Buffett said. "I feel the same way about the kid, but what I'm really thinking is, 'Is he going to pee on me?'"

On foreign aid...

One thing Gates is concerned about is how committed Trump is to maintaining foreign aid programs that he argues are a major force in global health.

"This administration is new enough, we don't know how their priorities will come out," Gates said. "There are things like foreign aid...that every time there's new leadership, we have to go in to articulate the benefits."

"Now, I think there's a lot of intensity to make sure that message goes out," he added.

He pointed to a malaria initiative and AIDS relief aid -- which were started under George W. Bush's administration and continued under President Obama -- as examples of programs he hopes Trump will see through.

"If we draw inward [on that spending] we will hurt progress and there will be millions of lives lost because of it," Gates said.

On immigration...

Buffett isn't a fan of the anti-immigration rhetoric that's been spearheaded by Trump.

"This country has been blessed by immigrants, and you can take them from any country you want, and they've come here and they've found something that unleashed the potential that their home country did not," he said.

On political donations...

Gates and Buffett are major philanthropists. They started the Giving Pledge in 2009. It encourages billionaires to commit to giving away the majority of their wealth before they die. One thing they're not fans of spending money on, however, is politics.

"We have a podium of a certain sort," Buffett said. "The influence of money in politics is really bad news for this country."

"We've chosen not to have that be a huge way we're spending our money. The money is being saved for, not the megaphone, but the work of the foundation," Gates said, referring to the Bill and Melinda Gates Foundation.

Despite their commitment to keeping their dollars out of politics. Buffett doesn't stay mum on the topic. He was an avid supporter of Hillary Clinton.