english: It certainly seems that we're going about our lives, that what we're doing, who we're with, what we're thinking about, have a big influence on our happiness, and yet these are the very factors that have been very difficult, in fact almost impossible, for scientists to study.
non_english: Každopádne to vyzerá tak, že je to o našich životoch, že to, čo robíme, s kým sme, o čom rozmýšľame má veľký vplyv na naše šťastie, a predsa práve tieto faktory sú tie, ktoré je veľmi ťažké, dokonca takmer nemožné skúmať.