Wouldn’t life be boring if everything were perfect?
I am not going to waste my time preaching that making mistakes is OK and that too many classical musicians are obsessed with perfection. Honestly, I don’t think it will make much of a difference. What I will say is what I love about live performance.
I love when a musician is immersed in the music, when they are wrapped up totally in what they are doing and they are having a great time doing it. When a performer arrives in the limelight and conveys a sense of relaxation, I feel relaxed and when they love the music they have chosen to learn, whatever style that may be, I will be more engaged than if they had picked music to please me (the audience).
I love it when there is some interaction with the audience so I get a sense of the person with the guitar in their hands. When something happens in the concert that is unexpected, a phone call, a strange sneeze, a booming stereo from a passing car, I love it when the performer goes with it and acknowledges it. Maybe they will even incorporate it into their performance?
When it’s a beginner on stage I love watching them accomplish a goal. I love seeing a sense of satisfaction and for them to accept compliments. If I wanted to hear world class renditions of a musical score I would go to Carnegie or Wigmore Hall, but for my local guitar society I want to connect with people who have a similar passion, that borders on an obsession. I want to see them grow, and to see them smile after bashing through whatever piece may have been in their crosshairs for the past 3 weeks/decades.
And as for mistakes, I don’t remember hearing any!