The man and the woman look a tad unhappy.

However, rotate the picture around and they instantly cheer up.

The ability to transform a bad mood into a good one is crucial in everyday life.

In a study from the University of Miami, volunteers were asked to describe something bad that had happened in their life, and then list one way in which they'd benefited from the experience.

Some said they discovered what mattered in life, or they found out who their real friends were, or they discovered an inner strength.

This simple exercise made people feel happier, less stressed, and even had a positive effect on their health.

So, when something bad happens, ask yourself just one question: How did you benefit from the experience?