You think about how by forgiving people: your neshama is cleansed ,you go up one madreiga and Adquire great merit for yourself . Every person is a shliach from Hashem and the hardest mitzvos are the source of the greatest reward. By not forgiving the person 100% you become attached to the attribute of din ….you become an accuser like the Satan lo Aleinu and liabable for punishment for delaying redemption like in the kamsa and bar kamsa story were one party refused to let go of hatred.
Please hasten our redemption and free youself .