There is a special feeling at Davies Hall in summer. The weather is balmy, if we are lucky. The sun is still up as the concert begins. But our hair is let down. Children are present, and young people dot the aisles in remarkable stages of undress. The air of eager informality is like a visit to the movies—minus the smell of popcorn. And, musically speaking, here we sometimes get the chance to hear romantic rarities we secretly love.