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 they need to rally around their own, they find a way to do so. William H. Macy, as the usually unreliable patriarch, seems to start out this season, the show’s eighth, on his best behavior – but even that’s not saying much. Emmy Rossum, as Fiona, is a powerhouse player in this ensemble drama, but each family member, on this series, gets his or her turn in the sun. And in the gutter…