6. Joe Green

Missed: Facebook

He infamously designed facemash with Zuckerberg while at Harvard. His father who was a professor at UCLA asked him not to work with Zucky again. Joe listened to daddy dearest and turned down Mark’s offer to be the business head for Facebook.

He still scored some Facebook stock for being an advisor to the company and he later cofounded Causes and NationBuilder, companies other early Facebookers backed. But he admits that sometimes there is the feeling of ‘bitterness’.