This post is more a reminder to myself, as I keep searching about happiness formulas and reasons for unhappiness / poison behaviours.
I just watched the video bellow (O que acontece quando pessoas desenvolvedoras de software ficam (in) felizes?), based on this article.
Take a look on the consequences of unhappiness and happiness.
Development goes beyond code, product and methodologies.
Different methodologies (e.g. scrum/kanban) will not address unhappiness issues.