In the Lords Prayer I prefer the forgive debts version over the forgive sins version. This is how I think of it
A debt is something you are owed within a system of borrowing and exchange. If someone owes me a debt it means that the system agrees that the debt is owed. Justice is served when the debt is paid. If they don't pay I can use the law to collect. When someone has wronged me justice demands that they pay me back in some way. The idea of justice implies that the universe somehow agrees that my claim is just. Forgiveness, in this context, means erasing the debt.
Forgive us our debts is usually taken to mean that I'm guilty within the cosmic system of justice but God can make an exception for me because I admit guilt and I'm trying to get it right. This is very much like a liberal justice system. But if I take the debt to be a sense of debt within myself then forgiving the debt means erasing the sense of debt from within me. It is a request to be freed from an emotional attachment to a false belief in cosmic justice.
“As we forgive our debtors,” can also be interpreted in a similar way. Here I believe that the cosmic justice system owes me because someone has wronged me. I feel I am owed restitution or compensation and that includes punishing those who wronged me. But, “as we forgive our debtors,” means I should not attach to the idea of justice being owed to me or to anyone. I should erase those debts. I should let go of any sense that I am owed anything.
Essentially, I owe nothing and nobody owes me. This seems like recipe for social disorder but that's only if you take it in isolation. The liberal justice system metaphor is also a legitimate way of understanding this part of the Lord's Prayer. Here the emphasis is on following rules and begging for forgiveness when you fail. I think both are right and also each is the antidote for the other. In Buddhism, an antidote is a thought that undoes another thought. Usually antidotes are thought of as countering harmful ideas, but in this case the antidotes balance each other. I like this version because I feel that Christianity is in need of rebalancing, away from an excessive focus on sin, guilt, justice, and retribution. More generally, I think it is a good practice to find balance in contradiction.