The finale of The Simpsons’ 15th season airing at 8pm Sunday includes pointed social satire, Capraesque small-town sentiment, broad physical humor and sly self-referential jokes. What it doesn’t have, in a time when sitcoms like “Friends” and “Frasier” featured plot arcs that played out over the course of a year, is any reference to the fact that it’s the last show of the season. In The Simpsons, everything is neatly tied up at the end of an episode. Bart is forever in fourth grade, and Maggie, the baby, will never talk. That consistency is one reason the show is one of the longest-running sitcoms in history. As actors on live-action programs age, “the viewer looks at it and says, ‘The show isn’t the show I loved 10 years ago,”‘ said Al Jean, the executive producer. “That doesn’t happen to us.” Since the writers long ago used up the obvious stories about the family, many plots now focus on the secondary characters who populate their hometown. Read More >>>