We live in a world in which we share experience more virtually and less physically than we ever have. We are surrounded by manufactured realities that distance us from actual people and events. Steven Moffats writing often reflects this strange paradox of connection and alienation and Last Christmas is no exception. The dream world is a grim research station haunted by a terrifying alien presence yet each character within the dream finds a sense of connection and purpose that is missing from their everyday lives and thus are reluctant to leave the dream when the opportunity arises. Enemies that use your own weaknesses against you are the most chilling and effective. Moffat in turn exploits the vulnerability of the rigid expectations of the audience by subverting perceived reality time and time again. It's a clever way to teach the viewer to question everything they see in the same way the Doctor attempts to train the people around him.