The biggest roadblock keeping you from your goals is that nagging feeling in the back of your head saying, "I might fail."
Completing the Stranger Challenge subjects you to failure and rejection. You learn to stop letting that fear hold you back.
I started talking to him randomly about the book I am reading. (The 4-hour workweek) by Mister Tim Ferriss. Then I realized I could probably take a picture too. I guess I am not that shy.