Statistical studies of happiness are interesting, but I feel they are borderline useless for practical application. There's just too much subjectivity lost in the quantification of happiness. Individuals are not populations.

On a personal level I feel the fastest way to feel unhappy is to worry too much about whether I am happy. Trying to design a goals or future state in pursuit of happiness feels like setting myself up for disappointment. All else being equal, having money is better than not having it, being engaged in some mentally challenging "work" is better than being bored, having good family and friend relationships is better than being isolated, but trying to optimize these things with some kind of master plan feels like it induces FOMO and general anxiety about the finite possibilities for one life.

I prefer to go with the flow, stay engaged in whatever I'm doing, and keep my eyes open for opportunities. I'm not sure if this makes me "happy", but I'm sure more content when I'm operating then when I try too hard to size up the big picture.