Initial results with the interventions have been promising, but sustaining them is tough. Months after a study is over, the people who have stopped the exercises show a drop in happiness. Like a drug or a diet, the exercises work only if you stick with them. Instilling habits is crucial. Another key: "fit," or how well the exercise matches the person. If sitting down to imagine your best possible self (an optimism exercise) feels contrived, you will be less likely to do it.
The biggest factor may be getting over the idea that happiness is fixed--and realizing that sustained effort can boost it. "A lot of people don't apply the notion of effort to their emotional lives," Lyubomirsky declares, "but the effort it takes is enormous."
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