If you're looking for reasons to be cheerful, then researchers have found one to top your list - happy people live longer.
A 30-year-long study found that miserable people of all ages were 14 per cent more likely to have died by the end than those with a sunny disposition.
Regardless of income, health or marital status, people who described themselves as "very happy" at the study's outset were more likely to outlive those who said they were "not too happy".
The "not too happy" group were also an average of 6 per cent more likely to have died at any given time than those who said they were merely "pretty happy", the study of 30,000 adults found.
One possible explanation for happiness aiding longevity is that happier people are better able to handle stress, and have a strong network of friends.