Self-made billionaire Ray Dalio is the founder and co-Chief Investment Officer of the world's largest hedge fund, Bridgewater Associates, which manages about $150 billion. "Although he has been called 'the Steve Jobs of investing,' employees don't communicate with him as if he's anyone special," writes bestselling author and Wharton professor Adam Grant in "Originals."

Consider this email that a colleague sent to Dalio after a meeting with an important potential client:

Ray — you deserve a "D-" for your performance today … you rambled for 50 minutes … It was obvious to all of us that you did not prepare at all because there is no way you could have and been that disorganized at the outset if you had prepared … today was really bad … we can't let this happen again.