True Happiness

This is a psalm addressed to God and to the "nations."  Where do we come in?  What are we able to hear that is addressed to us?  And what's to be done about these ranting nations?

The one who rules in heaven laughs'

my Lord makes fun of them. (2:4)

The Lord of this psalm sits on high and looks down, way down, upon the world's scheming, plotting rulers.  Everybody on earth trembles before these earthly tyrants; the Lord simply looks down and laughs at them.  It's a rare occasion when God laughs.  What sort of divine laughter do we have here?