With 'Good Will Hunting ' Miramax made certain the recruited audience wasn't expecting to laugh at Robin Williams like they normally do. From my limited experience you can really blow test screenings by conducting them in the wrong way.
I think when you begin to think of yourself as having achieved something then there's nothing left for you to work towards. I want to believe that there is a mountain so high that I will spend my entire life striving to reach the top of it.