The story illustrates an improper attitude of one who is destined for the kingdom of God. The Particulars 10,000 talents is an impossible amount to repay. This is important because it points out that our debt to God is one we could never repay. That is why hell lasts for eternity. The image of being released from a debt is a great illustration of what it is to forgive.
People are confused.
But it doesn't. You know they owe you, but when you don't make them pay, you know that it cost you. We don't forget. We can't forget, but we don't hold a grudge. We don't bring it up again.