SEASON PREMIERE: This Showtime series, which began as an Americanized version of a British series of the same name, has, like The Office, found a successful home and identify of its own on this side of the pond. There aren’t many series that pull me in as effectively as this one, making me wonder and worry about these characters and the often self-destructive choices they make. The Gallaghers are one majorly dysfunctional family – and yet, somehow, they continue to function, and when