What is your ability to hold a grudge against someone like? Are there individuals in your life that you cannot stand and hold passionately bitter feelings towards, or do you see yourself capable as such? Why do you think you are the way you are in that domain of your life, and do you rationalize it?
Speaking for myself, I know that it is extremely difficult for me to hold a grudge for someone, no matter how much they may have wronged me in the past. I am lenient and can forgive and forget with tremendous ease. I know that some other people like this have rationalizations for not hating anyone or holding grudges, but I do not this is something that I do deliberately or consciously - I have no ethical or moral justifications for not hating people; it's just how I am. Even if I were presented with good reasons to hate someone (itself a highly debatable phenomenon), I still probably wouldn't.