Mark O'Mara is an angel investor and the founder of cloud storage company Dropbox. He says he made a mistake by selling his shares too early, which would have cost him millions in today's market. But it could have been much worse if they hadn't pivoted to give away free storage instead of charging users for their data. 'If you don't want me here, i don't need have other dinner parties,' writes O'Mara. "You should try and control your own destiny"