One amazing acting moment (possible spoiler)
When Anne Bancroft's character is at the hospital, trying to talk to a doctor, and the resident on duty leaves her to attend to another matter, and the admitting nurse is on the phone.
In one moment, Anne Bancroft's character goes from desperate to determined, and you see it in her facial expression. It's a fantastic transformation. Really, it's one of those amazing little moments that helps to define a great performance. It takes a great actor to pull that off, the beautiful subtlety of it, especially with the eyes. Anne Bancroft did it and made it look effortless. It's such a great moment, and the fact that it sticks with me makes the movie for me.