Perhaps more than anything else, failure to recognize the precariousness and fickleness of confidence - especially in cases in which large short-term debts need to be rolled over continuously - is the key factor that gives rise to the this-time-is-different syndrome. Highly indebted governments, banks, or corporations can seem to be merrily rolling along for an extended period, when bang! - confidence collapses, lenders disappear, and a crisis hits.