Yahoo’s CEO Marissa Mayer recently shared that some of the most valuable leadership advice she’s ever been given was by her former boss, Google founder Sergey Brin, as she walked out the door to join Yahoo in July 2012.

In a recent interview with Fortune, Mayer said, “As an engineer, my tendency is to be more conservative—to be more iterative. Even on innovation, I would rather bring out an early product and slowly make it better.” But while her natural style is to lean away from risk and apply caution to her business decisions, Sergey wanted to remind her not to let her innate cautiousness limit her decisions.

Mayer says she’s carried Sergey’s parting advice – “Don’t forget to be bold” – with her ever since taking the helm at Yahoo and that it’s been instrumental to some of the decisions she’s made. She said his words were replaying in her head as she made the call to acquire Tumblr and guide her decision around what to do with Yahoo’s stake in the Chinese e-commerce company Alibaba.

Of course, it’s easy for we lesser mortals to look at Mayer, a woman whose success seems to know no limits, and think, “Well it’s okay for her to be bold,” all the while justifying why we can’t afford to be near so daring ourselves. But as Mayer said in her interview,  if you want to do something transformational and make a difference in your own life and the lives of others, then you need to make bold choices, not just safe incremental ones. “Sergey knew the thing I’d need the biggest push on was to be bold,” she said.

It goes without saying that if it were easy to bold and brave, more people would be and Sergey Brin wouldn’t have felt it so important to encourage Mayer to do so.  The truth is that being bold is hard because it requires rising above our instinctual desire to avoid the possibility of failure, of losing face, our reputation or our job. All things Mayer’s had to lay on the line at every turn as she’s worked to turn the once faltering Yahoo ship around. (You may recall her bold and highly contentious move to cancel working from home and order everyone back into the office. I did an interview on Fox & Friends on this at the time which you can watch here.)

While some people are born trailblazers and risk takers, most of us aren’t.  It’s just not part of our psychological DNA to want to stick our neck out and lay our vulnerability on the line. Indeed, as I wrote in my book Stop Playing Safe, “We human beings are wired to play it safe.” Research by Nobel Laureate Daniel Kahneman found that when assessing risk, we have an innate tendency to focus more on what we could lose than on what we could gain.  Because of this, we tend to overestimate the probability of things going wrong and to underestimate our ability to handle the consequences of risk.

Not only do potential losses loom larger than gains, but we also have the cognitive bias of discounting the cost of inaction.  As University of Texas Professor Phillip Bobbitt found from his research, most people tend to downplay or ignore the opportunity cost of sticking with the perceived safety and familiarity of status quo. These cognitive biases and conservative tendencies combine to steer us away from bold and higher risk decisions and down the safer path.

While there is no easy way to overcome our innate risk aversion, it is important to weigh up the risk of not being bold. We need to be clear about what’s at stake either way. That is, what could it cost you to stick to the safer path and avoid the risks inherent with making bold decisions? As Mayer would likely tell you, not taking those risks can ultimately be far more dangerous that outright exposure.

Ultimately being bold takes courage. It boils down to making the choice to take action despite your fear of failure; trading the security of the known for the possibility of something even better. Just as nothing worthwhile can ever be achieved with a guarantee of success, there can be no boldness without risk. The lesson for us all is that while bold action may sometimes result in failure (Mayer’s had those, too), it is also what fuels innovation, builds edge and enables organizations to forge new ground in an increasingly accelerated, competitive and uncertain world.

Given the challenges many leaders and organizations are facing today, being bold is a piece of advice more of them should heed.