When Sallie Krawcheck graduated from college in the late 1980s, a slice of America's hotshot jobs were on Wall Street. Investment banking was one of the "extreme sports" of careers at the time--and Krawcheck landed a job at a top-five investment bank.

"It was horrible," she said on Inc.'s What I Know podcast. "The whole thing was horrible. It was the work ethic of 'mess around all day and then work all night. Mess around during the week and work all weekend. Leave at the last second for the airport so you could be sure to run for the plane.'"

By the time she turned 30, Krawcheck had transitioned to working as an analyst. In equity research, she learned a life skill that would serve her later, when she turned away from Wall Street to found her own banking, investment, and coaching company, Ellevest, which turned some of the biases that fuel big finance on their heads.

As a research analyst, she says, you'll never differentiate yourself by recommending the same reliable stocks everyone else is recommending. "If everybody's recommending Bank of America stock, and so you're comfortable and you feel good, then it's over already, right? Everybody's already bought it," Krawcheck said. "What you really want to be is contrarian."

Being contrary isn't easy--certainly not at first. But be contrary--and correct--enough, and slowly your opinions become the most valuable sort of opinions. "You are going to have to be uncomfortable before you are right," she said. 

Getting comfortable holding an uncomfortable opinion--or believing something unpopular--helped Krawcheck when she, after decades as a bank executive, put together a theory of women and financial investment. Finance had been, of course, dominated by men. It wasn't just the heads of banks or the 98 percent of mutual fund managers who were male. She'd seen a pattern of large sums of money leaving firms when inherited by or turned over to women; women actively rejected investing when given the choice. She knew it wasn't that women didn't have money or couldn't manage it. It was a system built without half of the population in mind at all. 

That there was a remarkable gender gap in investing and that she could change it was an uncomfortable opinion. But it proved a sturdy foundation for building Ellevest with women in mind. 

Krawcheck tells her story on What I Know. Listen in the player below, on Apple Podcasts, or wherever you subscribe to audio.