Happiness may be“U-shaped,”but a recent survey suggests that,despite their problems,the Chinese may be the world’s leading optimists.In“What Worries the World,”a study by global market-research firm Ipsos,87 percent of Chinese adults said their country was“heading in the right direction,”while 60 percent of citizens of 25 other surveyed countries considered theirs on the wane.Western Europe and other high-income nations—where contentment is said to decline between ages 18 and 40 before Happiness may be “U-shaped, ” but a recent survey suggests that, despite their problems, the Chinese may be the world’s leading optimists. “What Worries the World, ” a study by global market-research firm Ipsos , 87 percent of Chinese adults said their country was was “heading in the right direction,” "60 percent of citizens of 25 other surveyed countries considered theirs on the wane. Western Europe and other high-income nations-where contentment is said to decline between ages 18 and 40 before