Advent, of which we are in the final days, is a time of waiting. We wait to celebrate the incarnation of the eternal Son of God, Jesus. But we also await his return to rule the new heavens and the new earth with justice. This already and not yet can be seen in Psalm 85.
The psalmist begins with “You showed…” and a few lines later our writer says “Restore us…”
I suggest you look at the entire Psalm and in the last “stanza” we can see a study of the work of the Son of God:
“Love and faithfulness meet…”
“righteousness and peace kiss…”
If we consider his love, faithfulness, righteousness and peace, this can fill us with joy.
But this requires discipline. This is why we may see a correlation between a neglect of our focus on him and a lack of joy.
“Set your minds.”