Put the spatula, wooden spoon or whatever you’re working with down. Step away from the food. Food cooks by coming into contact with a hot pan or grill and it has to reach certain temperatures in order to reach doneness. Every time you stir/flip food, it loses contact with the pan and has to start cooking all over again. You extend your cooking time and may alter the food’s texture and color by moving it around too much.
An occasional stir is necessary to prevent sticking and to ensure all sides are evenly cooked, but don’t overdo it. When in doubt put the food into a hot pan and then…wait for it…let it cook.