Don't worry, be happy.
That's not just good life advice, it could actually help you live longer.
But if you ever needed a little persuasion to look on the bright side, here it is: happier people tend to live longer, healthier lives.
But you don't need to take our word for it. As Jane Brody reports for The New York Times:
Studies have shown an indisputable link between having a positive outlook and health benefits like lower blood pressure, less heart disease, better weight control and healthier blood sugar levels.
Whether you're living with a chronic condition already, or trying to stay healthy as you get older, there's evidence that a good mood is good medicine.
One study by the University of California gave a group of patients with HIV advice to "foster positive emotions."
The patients had lower virus loads than other groups by the end of the study.
Part of the reason why is the positive group was better about following their doctor's orders; positive people tend to look after themselves, and adapt to changes more easily.
If you're hoping to stay alive for a long time, a positive outlook is a must-have.
Patients with chronic conditions including Type 2 diabetes and even AIDS tend to live longer if they focus on positive emotions.
But just telling yourself to "cheer up" isn't good enough. Instead, there are some practical ways to boost your mood and keep yourself in good shape.