He's barely started his new gig and he's already proving his approach is the antithesis of Kalanick's. In fact, he took only eight words to do it.

The polar opposite of frat boy bluster.

Like any good leader, Khosrowshahi, the long-time CEO of Expedia (and a refugee from Iran) took the time to formally bid farewell to his employees and thank them for their hard work before leaving. So far that sounds like good but hardly astounding leadership. It's what Khosrowshahi included in that expected letter that should give hope to Uber watchers. Recode reports that in his parting memo Khosrowshahi admitted:

I have to tell you I am scared. I've been here at Expedia for so long that I've forgotten what life is like outside this place. But the times of greatest learning for me have been when I've been through big changes, or taken on new roles--you have to move out of your comfort zone and develop muscles that you didn't know you had.

Yes, you read that right, the new CEO of one of America's most brutally competitive startups flat out admitted to being scared. That's first and foremost a huge change from Kalanick's frat boy bluster and self-involvement, but it's also a great sign that Khosrowshahi may do well in one of the toughest jobs around.

Vulnerability is an underrated leadership skill.

Why? Because showing vulnerability isn't a sign of weakness. It's a huge source of strength for a leader and a powerful tool to build genuine trust by providing a safe space in which to discuss, experiment, fail, and innovate, according to experts.

"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," management consultant Peter Sheehan has said. "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."

By admitting to his understandable terror with eight simple words -- "I have to tell you I am scared" -- Khosrowshahi expresses just the sort of vulnerability that kills shame and allows a team to trust that if they also experience failure and fear (both pretty much a guaranteed part of doing anything great), their leader will understand and support them.