He used to sell insurance door-to-door when he was in college

His family returned to Brazil when he was 18, and he started selling insurance to make ends meet. All his friends, on the other hand, were rich.

From the Australian Financial Review:

"So I got highly motivated to make some extra money and I sold insurance policies from door to door. It's a great learning experience because some doors open and some don't. I had a lot of teas with old ladies."

But by 1979, he'd dropped out of college before he could finish his degree in metallurgical engineering and returned to Brazil.

Source: Robert the matador joins Eike the bull, Australian Financial Review, October 30, 1999 Saturday, Late Edition