I went to a theatre performance the other day. It was basically one actor on stage for over two hours. It was coming to the end of its seven-week run, but it still felt as fresh as the first time it was performed. How do you manage to keep a performance alive after so many repetitions? Seeing the show for the first time, it felt like it was a brand new performance, just for me. I worked out that the actor must have done the show at least 40 times in the current run. That’s not including the many previous...