It was a San Francisco moment. On Pride Sunday this past summer, I went up the stairs from MUNI to the street. I was on my way to the premiere of Hannah Free. As I reached the bottom of the short escalator to the street level a group of men burst into song. Ahead, another cluster turned and joined in. For about thirty seconds, there was musical theater in the subway station, and why not?

That spirit of music is something my daughter understands. She's the only person I know who can read and si...