Feelings….oh those feelings! This is a response to art that is primarily emotional, and is responding to the emotional expressiveness of the art. Happy, sad, or simply feeling moved deeply is all feeling.
Because 19th century Romanticism was a pinnacle of intense emoting – feeling, this type of feeling is called Romatic – sentimental. Leo Tolstoy described “Art as feeling”.
It also refers to the emotional intensity of the performance itself. We don’t respond as much to “emotionally flat” performances. Can’t you hear the director shouting “Now, once more….with feeling!”