Feeling emotionally connected to a song, and accumulating every bit of the moment's energy to sing out to the audience is what I believe makes a great performer. ↗
When you have a performer as talented as Bill Murray or as Harold, that can write as well as they can perform, you can do a final draft on the set if you think of it that way. ↗
All the best performers bring to their role something more, something different than what the author put on paper. That's what makes theatre live. That's why it persists. ↗