Meet Mason Wartman. In 2013, Wartman left his job on Wall Street to open up Rosa’s Fresh Pizza, a shop that sells slices of pizza for only $1 (tax included). The concept is popular in New York City and Wartman wanted to bring the idea to his home town of Philadelphia. One day a customer asked if he could ‘pay it forward’ and buy a slice for someone in need. Wartman loved the gesture so he drew a smiley face on a Post-It note and stuck it on the wall to symbolize a free slice for someone in need.