Some people are like a thermometer. If their environment is negative, they are negative. If bad things happen, they are sad. If good things happen, they are happy. They are simply a product of their environment. Successful people, on the other hand, are more like a thermostat. Even if their environment is negative, they choose to be positive

Some people are like a thermometer. If their environment is negative, they are negative. If bad things happen, they are sad. If good things happen, they are happy. They are simply a product of their environment. Successful people, on the other hand, are more like a thermostat. Even if their environment is negative, they choose to be positive (Cameron C. Taylor, 8 Attributes of Great Achievers)