It is not fun to be beholden to others. When we wrong someone we would just as soon pretend it never happened. But it is sometimes fun to have others beholden to us. I don't like to say “sorry,” but I do like to hear it. When people apologize to me it puts me in a position of power. Of course I will be benevolent to forgive them, I just want to know that they are truly sorry. This, of course, is not real forgiveness. Real forgiveness is not empowering, and does not require the repentance of the trespasser.
In order to truly forgive we do not need an apology. We just have to recognize our own sin against God to realize that we have no true claim against any other.