Forgive me as I forgive others (Matthew 6:12). God's forgiveness makes us forgivers. And the more we understand God's forgiveness and the atonement (just think of propitiation), the more we are able to live up to our identity.
As I've gotten older or because of some experiences I've found it harder to forgive some people who have hurt me, even when I recognize my role in the conflict with them. I use to be able to forgive and forget much more easily. My prayer time focused on that and how God--the only one who has no culpability in our conflict with him--has not only forgiven us, he has done it by absorbing his own perfect anger against sin.
Forgive as I forgive others would be a scary thing if God would hold us to that standard before accepting us or in order to continue to accept us. He doesn't. Our lack of forgiving is part of the sin Christ died for. But a growing ability to forgive is a sign that we have truly understood and received his grace. A growing ability. A willingness to struggle with it is evidence of God's grace. I want to grow in that grace. My identity is not only that I'm forgiven; I'm a forgiver.