Positive emotions such as optimism can improve mental and physical health as well as performance in academics and jobs. The broaden-and-build theory proposes that positive emotions broaden people's thought-action repertoires and build their personal resources. Optimism is a positive frame of mind characterized by believing that one has power over their life and future, that negative events are temporary and not reflective of who they are, and that positive events are permanent and influence other areas of life. Optimism provides benefits such as good health, motivation, self-esteem, satisfaction, effective communication, and an increased social life.