Until recently, psychologists believed that the degree to which a person can naturally experience happiness, referred to as a “set point”, was innate and unchangeable. We now know that, like weight, it’s more of a predetermined range of potential rather than a single fixed number. Genetics influence about half of a person’s total happiness level and circumstances another 10 percent.
But the other 40 percent is affected by “intentional activity”, meaning anything we do consistently and on purpose, whether a positive habit, such as regularly meditating, or a negative one, such as drinking excessively every night
Terri Trespicio, “Thank-You Therapy”, Body & Soul Magazine, Spetember 2008