I think the "surprise" also reflects elitism ... how could people who work blue-collar jobs, live in the suburbs and shop at Wal-mart be optimistic? Don't they realize how pitiful their lives are?
Indeed. How can people possibly be happy living in a 2000 square foot house, drive a used pickup, go to church, have BBQs on the weekend, beers in the tavern, and raise children. It's impossible, they say.