As I read the Psalms, one of the things that strikes me is how the psalmists so frequently use the dichotomy of the righteous and the wicked, with themselves playing the part of the poor, helpless righteous. The wicked--the ones who are always rich and healthy, who have no problems in this life--are oppressing them or causing some horrible injustice and getting away with it.
The trouble for me is that I identify with both sides. I want to be the righteous person, but I know my heart too well to ignore the fact that, at some point everyday, I am that wicked person. So it can be difficult for me to fully click with the psalmist when he writes, for example, in 73:27-28:
Those who are far from you will perish;
you destroy all who are unfaithful to you.
But as for me, it is good to be near God.
I have made the Sovereign Lord my refuge;
I will tell of all your deeds.
I know that I'm the unfaithful one. I know that I'm the wicked one. But, only because of Jesus, I am also--and more so--the righteous one. Not because Jesus makes me a better person (although I happen to think that he does, at least for me), but because my faithlessness is wrapped up in and covered over by his faithfulness. My unrighteousness disappears into his righteousness. My wickedness dissolves in the sea of his holiness.
You are the wicked one. You know the evil that you're capable of. You are, but in Christ, you're not. In Christ you are faithful because he is faithful. In Christ you are righteous because he is righteous. And I think it's good to live in this tension, knowing the evil you can so easily commit, but recognizing that all of your righteousness comes from, and is found in, Jesus Christ.