Two Dances, Two Shirleys
When Shirley does her little cockney dance with Arthur Treacher, this is the Shirley we love, the one who danced on the street for coins with Bill 'Bojangles' Robinson in the Littlest Rebel. The idiots who put spunky little Shirley in toe-shoe for a 'ballet dream sequence' when thousands of little girls across America in ballet classes could have done infinitely better) made the dullest scene in the movie.
Shirley thought of herself first and foremost as a dancer and when she is with Robinson, Treacher etc. one can see her light up with sheer sophisticated joy of an artist doing their art.