Haven't opened up the Psalms all that much since deciding to become Catholic. . . randomly opened up to Psalm 57, in which King David rails against his enemies:
Let death take them by surprise; let them go down alive to Sheol, for evil is in their homes and hearts.
But I will call upon God, and the LORD will save me. -Psalm 55:16-17
I must say that since becoming devoted to Mary, it's hard to relate to Psalms like this one in the sense that I can't see anyone around me as an enemy anymore - that is, nobody can separate me from the love of God nearly as much as myself.
This is such a precious gift from the Blessed Virgin: the awareness of such a deep sinfulness within us owing to the disordered state caused by inborn Original Sin, which baptism only starts the removal of. Everything becomes quite simple when the struggle is largely, indeed more and more exclusively with our own flesh: the traitor within who God must necessarily put to death over and over again, often by surprise and unexpected afflictions. At some point, we get so accustomed to these little deaths - the painful mortification of our wills - and we see that God is so faithful to rescue us from them that we can actually put ourselves to death of our own free will!
Such is the way of the Cross. . . the only way to the ultimate, beatific vision of the Holy Trinity.
And yes, if we are our own worst enemies, it follows that everyone around us - whether they treat us well or badly - is by comparison a good friend!