Anne McElvoy talks to American journalist Barbara Ehrenreich about her new book Smile and Die, which attacks what she believes to be her country's addiction to positive thinking and blind optimism. Taking examples from attitudes to serious illness, the success of motivation and happiness seminars and from politics itself, Ehrenreich tries to show that America's credo of positive thinking is undermining the country. And the peak of its damage, she claims, is the credit crunch itself, built on a rationality that brushed off all criticism of prosperity.