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Commencement speeches aren't typically renowned for their riveting content or brevity, but, once in a while, hopeful graduates get a speaker who is not only entertaining but also drops wisdom like a grenade and brings hungover graduates out of their seats.

These eight charismatic business leaders did just that when they gave their commencement addresses, making the grade for this unofficial list of the best quotes.

Time is precious.

L.A. Cicero | Stanford News

Late Apple CEO Steve Jobs gave one of the most memorable commencement addresses at Stanford University’s graduation in 2005, a year after he’d been diagnosed with pancreatic cancer. Jobs spoke frankly of his being adopted, being fired from Apple in 1985, and death -- which he said was a “gift” in its ability to make time count.

Related: Inspirational Advice From 10 Successful Leaders

Be too legit to quit.

UWTV | Youtube

Steve Ballmer is well-known for his over-the-top enthusiasm during speeches. At the 2014 graduation at University of Washington, the L.A. Clippers owner and former longtime Microsoft CEO told the graduates that he, at 58-years-old, had no clear plan of what he was going to do next -- but that success was a long-term trip, not an overnighter.

It isn’t the first time Ballmer has urged a crowd to “be hard core,” with an overabundance of energy.

Related: 3 Life Lessons From Steve Ballmer's Rousing Graduation Speech

Find someone to love.

University of Southern California | Facebook

At the University of Southern California this year, Mellody Hobson, president of Ariel Investments and chairwoman on several boards, not only spurred students to find someone to be passionate about -- but also to expand their bandwidth of diversity by getting to know people with whom they have seemingly nothing in common.

Related link: 30 Inspirational Quotes for Entrepreneurs (Infographic)

On the other side of failure is clarity.

Team Coco | Youtube

The comedian and TV personality Conan O’Brien spoke about his very public failure in 2010 when he was given NBC’s Tonight Show hosting gig (that once belonged to Jay Leno) only to be forced out of the role. He spent the following year “adrift,” he admitted, trying on new career moves such as doing stand up and touring on the road. The time, he said, yielded the most rewarding year of his career.

Related: 38 of the Most Inspirational Leadership Quotes

Careers are rarely clear-cut, upward trajectories.

Harvard Business School | Youtube

In her speech to graduates, Facebook COO Sheryl Sandberg spoke about her travails finding a job after graduating Harvard Business School and moving to Silicon Valley in 2001. At the time, Sandberg had been offered a job at Google, which she expressed to its CEO-at-the-time, Eric Schmidt, didn’t meet her job requirements. His response to her: “When companies are growing quickly,” said Schmidt, “careers take care of themselves.”

Related Link: Sheryl Sandberg's Advice to Grads: Banish Self-Doubt, Dream Bigger and Lean In, Always

Get started already.

Dominick Reuter | MIT News

Dropbox CEO Drew Houston returned to his alma mater to encourage graduates to become obsessed with something that matters to them -- and get started immediately. In building Dropbox, reportedly valued at $10 billion in 2014, Houston shared that his wins have been as magnificent as his failures.

Related Link: Dropbox CEO Gives Graduates His Cheat Sheet for Success

Punching a time clock is not the way to change the world.

UMN College of Science and Engineering | Youtube

Silicon Valley entrepreneur Steve Blank spoke to graduates of his realization that he wanted to do more than just be a “cog” after leaving the military as a youth and joining a big tech company. At the time, his friends working at startups were living in garages and were free to pursue their own ideas and cultivate their talents -- he made his choice and joined them.

Related Link: Steve Blank: 'Entrepreneurship is a Calling, Not a Job.'

Doing what you love creates resilience.

University of Michigan | Youtube

At the top of his humor-filled address, Twitter CEO Dick Costolo tweeted -- naturally -- then went on to warn graduates about there being no script for how careers unfold. He used himself as an example: As a graduate of University of Michigan, Costolo moved to Chicago to pursue improv comedy -- what many might consider a life of artistic poverty. While he didn’t remain in improv, he integrated valuable lessons that lead him to where he is now.

Related link: Twitter's Jack Dorsey Defends CEO Dick Costolo in Massive Tweetstorm

Bonus: Reality is harsh.

Please don’t sugar coat the message, OK? Thanks.