Dial M for Murder (1954)

Alfred Hitchcock had chosen a very expensive robe for Grace Kelly to wear when she answered the phone. The actress balked and said that no woman would put a robe on to answer the phone when she was sleeping alone but would answer it in her slip. Hitchcock agreed to do it her way and liked the way the rushes turned out. The director agreed to allow the actress to make all costume decisions for herself in their subsequent films together.