What is it with sports imports from Philadelphia? Last year, Donovan McNabb floundered on the football field. This year, it was the Nationals’ turn, as they spent $126 million for seven years’ worth of Jayson Werth, a career .270 hitter. Werth then posted stats like a .232 batting average, 58 RBI, and 157 strikeouts. By mid-summer, with Werth hitting .212, Nationals Park fans were making him feel right at home, assuming that home is Philly: He got booed before most at-bats. In postseason interviews Werth claimed the season was a success because he helped change “the culture” here. It’s true! In inspiring lusty boos, he’s helping Washington develop a surly baseball culture to rival old-time MLB towns. Still, he promises better things, telling the Post that “I’m not very good at failure.” He’s got only six years left to prove it.