div class=ts-pagebuttonPage 1button div class=ts-image amp-img class=ts-thumb alt=Page 1: SciHappiness Happify 28309Gruber J Kogan A et al 2013 Happiness is best kept stable: positive emotion variability is associated with poorer psychological health Emotion The src=https:reader034vdocumentssitereader034viewer20220502135f5f46410d398b51ee08d7ffhtml5thumbnails1jpg width=142 height=106 layout=responsive amp-img divdiv