As a commerce student at UNSW in the 1980s, David Tudehope, CEO and co-founder of Macquarie Telecom, used to study in the library. One night he came across a biography of former US president Calvin Coolidge that had been left on a desk. Someone had left a post-it note on a page, to which Tudehope, distracted from his studies, turned.

Tudehope – who would go on to build one of Australia’s most successful technology companies alongside brother Aidan, propelling them into the 2021 Rich Bosses list and, for the first time The Australian Financial Review’s overall Rich List – found a famous quote from Coolidge that resonated with him. Indeed, he was so taken by the quote that he carried it around in his wallet for a decade.