Psychology professor Sonja Lyubormirsky claims, your happiness is significantly influenced by your perspective – it’s intentional. When I go to those places that don’t serve me well and I feel that things aren’t great, I remind myself that I have a choice. But ‘reminding myself’ takes practice. Don’t avoid cliche suggestions: they work if you try them. Whether you do it openly or just remind yourself, remember to be thankful.
http://www.mindbodygreen.com/0-11819/scientific-proof-that-being-thankful-improves-your-health.html