These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Shortly after Susanna moves in, Valerie reminds Georgina that "yes means yes" and later, Georgina directly tells Susanna what mental illness she has (pseudologica fantastica). Then near the end of the film, Georgina shouts a few obvious lies. Other than these three brief events, not much is made of Georgina's disorder and she generally seems to be quite healthy.
Some deleted scenes show some very disturbing hallucinations of Susanna's, such as bending her hand in unnatural positions (this is when she believes that she has "no bones" in her hand), and of blood pouring out of the meat refrigerators at a supermarket. The best example for this trope from the book itself, though, would be when Susanna and a few other inmates go to the Maximum Security Wing to visit someone who was recently transferred from their wing. ...Let's just say there is a very good reason why some of the inmates there were locked up.
One-Scene Wonder: Vanessa Redgrave as Dr. Sonia Wick technically appears in three scenes, but she absolutely steals her sole major scene.
Lisa finally breaking down in tears towards the end of the movie.
The scene with Susanna and Valerie in the former's room, after she's returned to the hospital following Daisy's suicide:
Valerie: What would you have said to her?
Susanna: I don't know. That I was sorry. That I will never know what it was like to be her. But I know what it's like to want to die. How it hurts to smile. How you try to fit in but you can't. You hurt yourself on the outside to try to kill the thing on the inside.