Forgiving is just so hard...

Ephesians 4:32 (ESV) 32 Be kind to one another, tenderhearted, forgiving one another, as God in Christ forgave you.
Regarding forgiveness, Pastor Tim Keller writes:
 When speaking of forgiveness, Jesus uses the image of debts to describe the nature of sins (Matt. 6:12; 18:21–35). When someone seriously wrongs you, there is an absolutely unavoidable sense that the wrongdoer owes you. The wrong has incurred an obligation, a liability, a debt. Anyone who has been wronged feels a compul­sion to make the other person pay down that debt. We do that by hurting them, yelling at them, making them feel bad in some way, or just waiting and watching and hoping that something bad happens to them. Only after we see them suffer in some commensurate way do we sense that the debt has been paid and the sense of obligation is gone. This sense of debt/liability and obligation is impossible to escape. Anyone who denies it exists has simply not been wronged or sinned against in any serious way.
What then is forgiveness? Forgiveness means giving up the right to seek repayment from the one who harmed you.
Forgiveness is something that we all struggle with from time to time, or for some of us, on a daily basis. Knowing that Jesus Christ has offered forgiveness to us frees us up to offer the same forgiveness to those who have hurt, wronged or sinned against us. These principles apply to all our relationships: work, home, church and otherwise. I’m so thankful that, despite my great sin, God has pardoned me. Let us ask him for the grace to extend that forgiveness to others as well.
To read Keller’s entire article on forgiveness (which is excellent), check out this link.