How correct,the music dictates the facial expression. Save the grin for something exhilarating like the QS. This is a hard concept to sometimes understand, and people do smile when they are nervous, especially in the beginning when you have this feeling that all eyes are watching your every move. Maybe they were told to smile when they dance to cover up the nervous look that would have shone through otherwise? I remember those days well. They will relax inside and the music will take hold and be reflected in their facial expressions, give them time.