Fun fact: September 16 is the day in 1985 that Steve Jobs left Apple, and also the same day in 1997 that he returned to Apple as then-iCEO.
Jobs first left after CEO John Sculley ousted him from Apple's board of directors after both had tried to be "co-CEOs."
Jobs also filed papers that same day in 1985 founding NeXT, the company that he intended to use as a weapon against Apple. Instead, Apple wound up acquiring NeXT for $400 million in 1996. Parts of the NeXT operating system, NeXTStep, eventually became the underpinnings of Mac OS X.