As individuals, at any given time, some things are in our control (we can do) and some things aren't (we can't do). If we focus our attention on taking positive action on things within our control in contrast to things outside our control, we will experience more success, personally subjective progress, and better mental well-being.

Being able to tell what is within or outside ones on control isn't trivial and takes practice. Also, what's within our control (what we are able to do) changes over time.

Each individual example can involve subjectivity, but this meta-pattern is an objective truth of agents living in a complex universe.