Brad Hargreaves has built his career and several businesses on learning how to act on feedback about what's working while tuning out everything else. The lessons that helped him make thousands of dollars at a time selling furniture as part of a side hustle when he was an undergrad at Yale also helped him build a company that eventually sold for $412 million.

There have been big losses along the way too. Entrepreneurship is a rollercoaster. If it looks like Brad is having fun, and it definitely does, it may be because he's learned to not lose his head during any of the twists and turns.

1:00 Brad is a serial entrepreneur

3:31 Discovering Yale’s surplus card catalogs and turning a $50 purchase into a $3,000 eBay sale

8:43 Founding General Assembly. Graduating into the glo ...