7. Steven Sinofsky's 15 minutes

7. Steven Sinofsky's 15 minutes

What should have been the crowning achievement for controversial Microsoft executive Steven Sinofksy turned out to be his swan song.

Sinofsky has a reputation for being hard-headed and for getting things done. He was the exec who got the Windows franchise back on track and who drove the development of the radically different Windows 8. Just a few weeks after the new operating system was released, Sinofsky left Microsoft.

Sinofsky and CEO Steve Ballmer agreed it was time for him to leave, but we still don't entirely know why. We assume it was not that Windows 8 was so awesome he had nothing left to prove, and more like Windows 8 was finally out the door and Ballmer didn't want to have to deal with Sinofsky anymore.

In case you're counting, that's three PC operating systems in five years for Microsoft and two executives in charge of said operating systems who left the company not long after they were released. Tough gig.