Dear Jan,
I would never even want to forget, because someone's ability for justice is part of how I relate to them...
Typically I don't even find myself in the "line of fire" for injustice, because I start with my own sense about people, and if they are incapable of justice I would just duck and dodge those situations, pre-emptively. So if they do me an unexpected injustice, I simply adjust my relationship with them.
But you must always fine-tune also; as people grow in the way of love, over the years of their life, their capacity for justice expands.
* * *
Actually, I usually make it a point to trust people a little beyond their ability, just for room to grow...