In Poetics, Aristotle says that four things are necessary in the creation of a good character: goodness, appropriateness, likeness, and consistency. The scene in Skins, then, that establishes Cassie as a “good” character is when she is at the clinic getting checked out.
1.) Goodness: Cassie clearly has an eating disorder, but the clinic seems no place for her. In the scene, we watch the money-hungry clinic director carelessly check off boxes to sign Cassie out in between shots of a crazy man running naked across the lawn. The viewer gets the sense that Cassie isn’t as crazy as that man and that she’s not being taken care of at the clinic the way she should be; her deeper issue seems to be feelings of neglect (her parents are in love with each other more than they care about Cassie), and Cassie is clearly being neglected at the clinic.
2.) Appropriateness: Like most anorexics, Cassie is clever at hiding her weight loss–we see her being clever when she stuffs weights into her clothes so that she seems heavier than she is before her final weigh-in; this character trait marks her appropriateness at a clinic, but not necessarily this clinic.
3.) Likeness (Likeability?): Cassie has a big smile and is kind to everyone she meets. She kisses the clinic director on the way out of the clinic–which is a strange thing to do, but sweet nonetheless. She is a pretty girl, who attempts to establish meaningful relationships with those around her.
4.) Consistency: One of the dead giveaways that Cassie is lying is when she opens her eyes really wide and we see the top white part. The clinic director would know that Cassie was lying about being fine if she looked at Cassie closely, or with concern, during the meeting.