I just don’t know if I agree with the concept that continued negative responses within me are a sign of lacking forgiveness, or middos, or not doing ratzon Hashem.
I think this concept IS applicable and correct, to a person who is entirely a malach.
But it is something to strive TOWARDS, though you know it is not possible to get there. To whatever extent, it IS something worthwhile to work on. I believe trying to achieve this IS doing the Ratzon Hashem.
If it is truly a horrendously difficult and painful situation, even a bit of an attempt, and even occasionally when you are particularly inspired to do so and feel spiritually strong, I believe is tremendously worthwhile.