Harry's status as orphan gives him a freedom other children can only dream about (guiltily, of course). No child wants to lose their parents, yet the idea of being removed from the expectations of parents is alluring. The orphan in literature is freed from the obligation to satisfy his/her parents, and from the inevitable realization that his/her parents are flawed human beings. There is something liberating, too, about being transported into the kind of surrogate family which boarding school represents, where the relationships are less intense and the boundaries perhaps more clearly defined.
