Lack of employment opportunities involves both those without work and those who have jobs but want to work longer hours or more productively. To individuals already employed it means lack of a reliable way of increasing income, achieving promotion and acquiring self-esteem. For societies, unutilized or underutilized skills are potential productive resources that are wasted. In some cases even where incomes are sufficient, lack of upward mobility causes resentment by individuals who feel they are missing opportunities which they feel they deserve. For developing countries, insufficient paths of advancement within employment means an inability to build a technical, professional or managerial infra-structure.