Director George Cukor wanted Anna's recital of her life story to be done in a tired, mechanical fashion, so he had Joan Crawford repeat the multiplication tables over and over until he got the monotonous tone he was looking for. Then, he rolled the cameras.
This was originally an MGM project lined up for Greta Garbo, but she retired from films, and MGM rushed Joan Crawford into the role.
In Boze Hadleigh's 1996 book 'Bette Davis Speaks", he asks Davis whether Joan Crawford ever did a role that she wished she'd done. Davis replied, "Il était une fois (1941), which her friend George Cukor directed. A complex role - woman with a scarred face and personality." She also mentioned Humoresque (1946).
Twenty-four years after this film, Joan Crawford presented George Cukor with his only Oscar for directing My Fair Lady (1964).