I think forgiveness is required of us because we will surely need it on ‘that’ day. What goes around comes around; we can’t expect it if we don’t give it.
Also, remember, Jesus commanded us to forgive. I can’t recall him telling us to forget. Indeed, I think he’d be impressed if we forgave and then used shrewd judgement in dealing with that person or those people again. It would be foolish in the extreme to keep lapsing into the same situations where we need to forgive again and again because he/she/they have ‘taken us for a ride once more.’
There was a guy on Australian 60 Minutes some years ago. His daughter had been brutally murdered years prior, and he had been brought face to face with the killer (now convicted and doing time for it). It was one of those ‘victim-offender’ meetings where the victim’s family gets to confront the killer in a controlled setting.
Anyway, the father forgave the killer.
The TV interviewer asked, “How could you forgive that person?”
The father said, “I didn’t forgive him for him, I forgave him for me. I had to do that to get on with life.” (paraphrased, but pretty close).
That’s true forgiveness.