Testers are what keep this business going.  Every time I put out a call for testers I am blown away by the people that want to help me with my patterns.  As I start to see the versions pop up in the testing group I get more and more excited.  I had a friend ask me recently what it was like to see your work on other people, and I am not sure I can put it into words because it really is amazing each and every time.