You can think yourself happy: study

Want to be happier? Then try to be so!
Scientists have found that actively trying to be happier can actually make you happy.
Two US academics, Yuna L Ferguson and Kennon M Sheldon, in a study published in The Journal of Positive Psychology, described experiments they conducted into 'trying to become happier'.
In the first study, two sets of participants listened to 'happy' music. Those who actively tried to feel happier reported the highest level of positive mood afterwards.
In the second study, participants listened to a range of 'positive' music over a two-week period; those who were instructed to focus on improving their happiness experienced a greater increase in happiness than those who were told just to focus on the music.

What seems to have made one group so much happier than the other in their respective studies was a combination of actively trying to become happier and using the right methods - in this case, listening to happy music.

The findings challenge earlier studies suggesting that actually trying to become happier was, in fact, counterproductive.
"[Our] results suggest that without trying, individuals may not experience higher positive changes in their well-being," the researchers wrote.
"Thus, practitioners and individuals interested in happiness interventions might consider the motivational mindset as an important facet of improving well-being," they said.