This poster in Facebook's office inspired an early employee to make a huge career shift in his 40s

"What would you do if you weren't afraid?"

For four years, that's the message Paul Ollinger saw every single weekday, on posters plastered all over Facebook's offices. Only recently did he realize what his personal answer was.

"I would do comedy," he told Business Insider. "That's what I'd do."

Ollinger worked in sales at Facebook between 2007 and 2011, making him one of the company's first 250 employees.

Today, at 47, he's an Atlanta-based standup comedian and the author of the new book "You Should Totally Get an MBA," a comedic guide for those debating whether to apply to business school. He's never been happier.

That's not to say that the transition to comedy was easy. In fact, it was somewhat terrifying.

Ollinger had known that he had a passion for comedy pretty much since his first year at business school, at the Tuck School of Business at Dartmouth in 1995. He was asked to co-host the school talent show, and found it thrilling to tell jokes in front of a crowd.

At the time though, he though it would be wiser to graduate and find a steady job that would allow him to pay back his student loans and support the family he hoped to have.

Between 1997 and 2014, he worked at LAUNCH Media, which was later acquired by Yahoo!; Facebook; and a social ad technology company called Shift, with a two-year break in between to work in improv.

In 2014 he decided to pursue comedy full-time.

Perhaps the biggest challenge he's faced is being a beginner again, after becoming somewhat of an expert at his craft at Yahoo!, Facebook and Shift.

"Sometimes I drive to an open mic 30 miles away and bars to tell jokes for 10 minutes to half-drunk millennials," he said. "So I'm literally getting out of my comfort zone, literally leaving my wife who's watching TV in bed so that I can go and get better at this craft."

Still, he said, "I got a point where I couldn't not do it, that I had to just say, 'This is what I'm going to do,' despite not knowing how I would actually finish a project or knowing whether or not it would be good. I had to be okay to risk bombing at 47 years old in a comedy club."

In other words, he had to at least pretend he wasn't afraid of standing on that stage and trying his best.

Thinking back on the "What would you do if you weren't afraid?" attitude, Ollinger said, "That's a pretty insightful guidepost into doing what each of us is supposed to be doing. And if each of us is doing that thing at which we're the best and or most passionate, then I think the world is better off."