The director Matthew Warchus swathes the production in flourishes, many of them at least partly charming: a galaxy of warm, twinkling lanterns suspended above the stage; a preshow in which the company plays carols and tosses cookies and clementines to the audience; showers of brightly lit foamy snow that will actually melt on your face. But there’s no disguising Thorne’s limp, self-satisfied script, which feels less magical than simplistically Freudian. A Christmas therapist’s couch.