This implies that when we are out of focus it leads to unhappiness and the reciprocal is also true: no Matter the task you are doing, if you are focused it will bring a higher level of happiness than if you were to achieve a higher scoped task without focus. Again, the nature of the things we are doing has not impact on our happiness as long as it has sufficient level of interest leading to focus.
This concept brings equality where we could be unequal from one another.
To phrase it differently, if your object of attentions are not well defined (as in your attention drifts or lack of longer term perspective) it will tend to lead to unhappiness.
Explore the Notion
Source: https://www.science.org/doi/10.1126/science.1192439
Source: https://news.harvard.edu/gazette/story/2010/11/wandering-mind-not-a-happy-mind/