In personality psychology, people reliably differ from each other depending on four key aspects: beliefs in luck, rejection of luck, being lucky, and being unlucky. People who believe in good luck are more optimistic, more satisfied with their lives, and have better moods. People who believe they are personally unlucky experience more anxiety, and less likely to take advantage of unexpected opportunities. One 2010 study found that golfers who were told they were using a "lucky ball" performed better than those who were not.