MISSING OUT ON BILLIONS: These 10 People Made Some Of The Saddest Choices In Tech History

Atari founder Nolan Bushnell turned down the opportunity to invest $50,000 in seed money in Apple. At Atari, Bushnell was one of Steve Jobs's first bosses.

Had Bushnell said yes, he would have owned a third of Apple, a company that is today valued at more than $400 billion.

Ronald Wayne, Apple's third cofounder, sold his 10% stake in Apple for $800 two weeks after launch. He later got $1,500 for renouncing all claims to ownership.

If he had kept it, it would be worth about $40 billion today.

Back in the 1970's Steve Wozniak worked for Hewlett-Packard designing engineering calculators. In his spare time, he created a PC that would later become the Apple 1 computer.

Five times, Woz begged the executives at HP, lead by then-CEO John Young, to manufacture his PC. They said no. So he left HP to start a company called Apple with his buddy Steve Jobs.

Mark Zuckerberg's college roommate, Joe Green, turned down an offer to help Zuckerberg start Facebook.

When the two were at Harvard, they created a Hot-or-Not style website called Facemash, which got the pair in trouble with the university. When Zuck asked Green to help him with Facebook, Green's dad discouraged his son from doing another project with Zuck.

Had Green joined the company in those early days, he would have gotten about about a 5% stake, he thinks, which today would be worth about $3 billion.

Facebook got its start in Zuckerberg's Harvard dorm room. And it might have stayed in the Boston area if Battery Ventures, a venture-capital firm based there, hadn't walked away from negotiations with Zuckerberg back in 2004.

Battery Ventures partner Scott Tobin, who was involved in that meeting, later called Facebook "the biggest fish that ever got away.”

A few years ago, tech investor Bessemer Venture Partners published what it called its "anti-portfolio." That's a list of companies it could have invested in, but didn't. It was a fresh and entertaining look at the VC world.

One of the best stories is how partner David Cowan missed his chance to seed Google. Cowan’s college friend, Susan Wojcicki, had rented her garage to Sergey Brin and Larry Page as the first office for Google. She tried to get Cowan to meet with them.

Instead, Cowan painstakingly avoided the garage and the two cofounders at work there.

Last spring, Brett O'Brien's startup Viddy was a sensation. Photo-sharing app Instagram had just been acquired by Facebook for $1 billion, and Viddy—often called the "Instagram for video"—had about 30 million monthly users.

Twitter reportedly came looking to buy the company for somewhere in the $100 million range, but Viddy walked. (O'Brien denies those reports, saying the Twitter talks didn't progress into an actual offer.)

Too bad O'Brien didn't get Twitter to make an offer. Viddy's popularity has since taken a nosedive and O'Brien just lost his job as CEO.

It's been six years since Apple launched its gaming-changing iPhone and BlackBerry is only now coming up with a credible challenger, the BlackBerry 10.

The general consensus is that this is too little, too late.

There was a moment in 2008, when BlackBerry—then known as Research In Motion—could have saved itself. Its users were fanatically loyal and waiting for the touchscreen BlackBerry Storm. But the Storm was buggy and hard to use, sending them into Apple's arms.

RIM cofounder Mike Lazaridis stepped down as co-CEO in late 2011, and recently quit BlackBerry's board of directors, severing his last tie with the company.

Yahoo CEO Jerry Yang infamously turned down a $31-a-share, $44.6 billion offer from Microsoft in 2009. 

Many shareholders were unhappy and wanted Yahoo to sell. All the drama sent the company into a downward spiral for years. Only now, with former Google executive Marissa Mayer in charge, is Yahoo finally on the mend, it's stock trading in the mid-20s.

Still, who knows what the search engine market would look like today if the No. 2 and No. 3 search providers had combined in 2009?

Andrew Mason turned down a $6 billion buyout offer from Google. Instead, he opted to take Groupon public.

The IPO raised $700 million, and the company was briefly valued at more than $12 billion. But the stock promptly tanked after Groupon missed earnings forecasts and struggled with its accounting. A month ago, Mason reported he'd been fired, and cofounder Eric Lefkofsky and board member Ted Leonsis took over as co-CEOs.

The 25 Most Creative People In Tech