We all know that truly great leadership is hard. You need to balance setting goals with avoiding micromanaging, offering constructive feedback with boosting confidence, empowering others with making the tough calls.

But even if you master both business strategy and the fine art of communication, you can still fail. How? According to Quartz's Aimee Groth, all you have to do if never show your emotions.

Wait, what? Aren't leaders supposed to bottle up their own feelings to spare their team from having to deal with their personal ups and downs? It's a common misconception, but Groth gathers together various experts who all insist that great leaders don't just demonstrate strength, they also let their people see some of their fear, stress, and uncertainty. In short, real leaders don't act superhuman -- they show their vulnerability.

Why leaders need to be vulnerable

"By opening up about failures, leaders signal that it's OK to struggle and to fail," explains Groth, who cites this quote from management consultant Peter Sheehan to back up his claim.

"The secret killer of innovation is shame. You can't measure it, but it is there. Every time someone holds back on a new idea, fails to give their manager much needed feedback, and is afraid to speak up in front of a client you can be sure shame played a part. ... If you want a culture of creativity and innovation, where sensible risks are embraced on both a market and individual level, start by developing the ability of managers to cultivate an openness to vulnerability in their teams," he says.

Popular TED speaker and author Brene Brown agrees. Conflating success with perfection makes you risk averse and a hostage to the judgment of others, she notes. "When identity is attached to the success or failure of your company/ performance/ product, then 'you've handed your self-worth to what people think,'" writes Groth, quoting Brown.

Content strategist Sara Wachter-Boettcher has put this slightly different elsewhere. "You've probably heard about the importance of empathy," she wrote in a blog post. "We can't begin being empathetic when another person arrives. We have to already have made a space in our lives where empathy can thrive. And that means being open--truly open--to feeling emotions we may not want to feel... Empathy begins with vulnerability."

The bottom line: by sometimes admitting to failure, struggle and negative emotions, leaders free not only themselves but their teams to try new things and express their full humanity. Lack of vulnerability means lack of genuine leadership.

When is the last time you were vulnerable in front of your team?