On the surface, it may seem that lack of job security is something undesirable.In Japan, for example, the daily newspaper Asahi reports a sudden rise in the number of businessmen who need psychological help for their clinical depression.But optimists claim that flexible people are essentially happier; more creative, and more energetic than people who are ______________.It is true that these days workers must be more ______________ - able to change to fit new situations.Indeed, pessimists point out that it is certainly a cause of ______________.Many people find an ______________ - a sense of self - through their work.When they lose their job (or are afraid of losing it), they also lose their ______________, or belief in their own ability.This causes worry and depression.