I know this topic has been written about several times, but I wanted to add how I view forgiveness as I feel it is a very important part of our Spiritual Development,
Forgiveness is a door. You have the power to open it and walk through.
By this I mean, if the door stays closed, then one has chosen not to open it because of not being able to forgive. Once you do learn to forgive, a door is opened to a whole new vista of Path choices and new ideas and a higher connection with Self and Source.
To forgive, one must learn to start with yourself. For how can you forgive others if you cannot forgive yourself.
To forgive is a cleansing of Spirit and Soul. Nor is it an easy task, but the lessons we learn by forgiving are infinite. It does not mean we forget, for the event that was created is already embedded in our minds. But when you forgive, that memory and associated emotion or other facets become much easier to handle. For there are lessons to be learned by what we experience, both good and bad, some more painful than others, some even traumatic, all have something that was a message that needed to be heard.
I suffered many years with issues of forgiving people for whatever reasons I had. It took me a long time to sort them out and then start with myself to forgive and know and feel what this really means. It will be different for everyone, for our experiences are not the same, but the concept or idea is.
To harbor all those dark energies which just feed upon themselves and stop us from proceeding forward on our journey is doing damage for as long as it exists. It is a very important part of our spiritual journey. We do not all progress at the same rate, so some of us get to forgiveness sooner than others.
You experience a greater sense of self peace. As I said, it is truly a cleansing and the effort has many rewards.
Mind you, this is only my opinion and how I perceive forgiveness, for we all do not think alike. But I wanted to share my thoughts in my own rambling way.