Work and attitude are important subjects that affect most of our waking hours. Work is what must be done regularly and purposefully to achieve goals and desires, while play provides fun and relaxation. Positive attitudes that are valued include things like money, knowledge, and work ethic, while negative attitudes are disliked. One's attitude toward work strongly influences their satisfaction and achievement. Attitudes can be grouped into types like utilitarian, ego-defensive, value-expressive, and knowledge-serving. Work is classified in different ways and influenced by various personal and organizational factors that impact worker efficiency and performance.