Facebook's Mark Zuckerberg takes on a personal challenge to learn new things and grow outside of his work at Facebook.
In the last few years, his personal challenges were:
2009 - Wear tie every day
Why? Because in 2009, Facebook was just about to take over the world. In order to win the respect of others and to show his professionalism, he encouraged himself to put on tie every day. It was also to demonstrate his seriousness towards every single day.
