News that Andrew Mason was fired from his post as the CEO of Groupon yesterday didn't come as a shock to anyone, least of all Mason himself. "I was fired today," he wrote in an email to his employees. "If you're wondering why… you haven't been paying attention."

It was classic Andrew Mason: Deviant, smart, hilarious, and perfectly in character. It was the response of the anti-CEO, the type of self-deprecating hero whose humility in the face of his own failure is inspiring. This is the persona Mason has more or less cultivated and perfected through his five-year tenure at Groupon. He perpetuated it through countless interviews and exchanges with the media, and, along the way, accumulated followers who love and cherish him.

But to his detractors--and ultimately his board--Mason is a character who could no longer lead Groupon through its real-life financial woes and business problems.

When times are good--and your company is growing at an insanely fast pace--you might get by being a fun CEO. But when times are bad--and they are certainly bad at Groupon these days, the stock price is down to less than $5 from $19 a year ago, with no clear evolution beyond daily deals in sight--being fun is definitively not enough. A company needs a leader with experience to resurrect a firm--or, frankly, to set it on a sustainable path--and Mason just doesn't have it.

Many entrepreneurs, especially MBA-types and former financiers, wear T-shirts and jeans to project a laid-back image and attract a certain tract of employees and followers. Mark Zuckerberg might be the perfect example--he'll don the sweatshirt occasionally as a nod to his days as a hacker and to inspire his employees. But he'll never deviate from the script his communications people have meticulously prepared for him. Not Mason. His naivete was genuine and likeable. He was just a dude who went to Northwestern to study music and ended up designing a social interaction website for a guy--Eric Lefkofsky--who would later become his co-founder and investor. It was serendipity.

"I was beyond stunned," Mason admitted to Chicago when he raised funding for what would eventually become Groupon. "I didn't know people actually did things like this."

Pretty much every single one of the profiles written about Mason starts the same way: That of the boy-wonder with the untucked shirt and uncombed hair and the aw-shucks-this-guy-doesn't-seem-like-your-typical-CEO-type. 

"Sliding into a chair at Japonais for an early lunch, Andrew Mason does not look like a multi-millionaire CEO," opened one Chicago magazine profile. A Vanity Fair story described Mason "wearing his usual jeans and long-sleeved button-down" with a messy "mop of brown hair...his face stubbly." The Chicago Tribune went so far as to call him a "jester."  

It wasn't just his physical appearance that made him such an unconventional CEO candidate, it was his personality and his near-theatrical performances. The list is long. As a stunt, he once presented New York City mayor Michael Bloomberg with a pony. He went on Charlie Rose, and compared Groupon to 'N Sync. ("Like we have had good tunes, but we're not The Beatles," he said.) He took an oddly specific salary of $575 and he became well-known for wearing gorilla costumes around the office, so often that it was referenced in filings with the Securities and Exchange Commission. Once, he did yoga in his underpants in his apartment, and then broadcast it on YouTube. Another time, he claimed to a reporter that he owned 20 cats. (He does not own 20 cats.) Back in college at Northwestern, he tried to start a fake tradition in which all students brought their mattresses to the center of campus and stacked them into one giant tower. ("I got a call from the school saying I would be responsible for all the mattress damage and ultimately shut it down," he told the school's alumni magazine.)

Being the CEO of a publicly-traded company never changed him, which may seem laudable in some contexts, but Mason's excesses as a performer and his outsized sense of humor took its inevitable toll.

Take, for instance, the Groupon Tibet commercial that aired during the Super Bowl in 2011. It made light of the Tibetan situation saying, "The people of Tibet are in trouble. Their very culture is in jeopardy. But they still whip up an amazing fish curry...and since 200 of us bought at, we're each getting $30 worth of Tibetan food for just $15 at Himalayan Restaurant in Chicago." The ad caused such a stir about its bad taste that Mason himself responded to the backlash in a blog post. Rather than simply apologize and move on, he defended the ad, writing, "We would never have run these ads if we thought they trivialized the causes."

In 2010, a Dartmouth business school professor rated him "One of the Worst CEOs of the Year." 

Still, it's remarkable and impressive that Mason lasted this long. Consider this: Of the 500 companies on the Fortune 500, just 23 are led by its original founder. So it's not surprising that Mason was ultimately fired--what was surprising (and entertaining, really) was Mason's ability to retain a sense of humor about being thrust into this role, and, for a time, use it to blossom as a smart and driven boss.

Ankur Warikoo, the CEO of Groupon India, describes Mason as "a smart guy, who is also a fun CEO."

Mason's rise and fall speaks volumes about the new generation of CEOs that came out of the early days of Web 2.0, when the barriers to starting a business came down, and new attitudes emerged about a casual, candid leadership persona. Today, anyone can be a founder. Only a select few founders can become true leaders. Many will fail before they do.

"I never thought of myself as an entrepreneur," Mason said in an interview in December 2010 with the Chicago Tribune. "I have a lot of ideas on things and I like to try and create things. Everything that's happened to me, it's just meeting up with the right group of entrepreneurial people who exposed me to this community and I've learned a ton."