These mutations can be either beneficial or detrimental. Oxygen impurities can have beneficial or detrimental effects. Competition can have both beneficial and detrimental effects. Individual characteristics are essential in deciding the most beneficial coping strategies. Reflective daydreaming can be both beneficial and detrimental. Weather can have both beneficial and harmful effects. Other organisms form mutually beneficial relationships with plants. They eat whatever they can catch, including both harmful and beneficial insects. The UV spectrum thus has effects both beneficial and harmful to life. It is unknown if early surgery is beneficial or harmful. Many cases of mutually beneficial interactions have evolved. Comparative advantage focuses on the range of possible mutually beneficial exchanges. Global city status is considered beneficial and desirable. Claims are made for beneficial antioxidant effects. Enthusiastic teachers are particularly good at creating beneficial relations with their students.