Holding grudges is one of the worst things a person can do. Its understandable that you can be mad at a particular person(s) about a situation that you will never erase from your memory, but are you gonna hold onto that forever?
Apart of taking this journey on Earth is knowing that people are going to piss you off. That people you though you can trust, care about, or associated with can do something to you that is almost unforgivable that yes you will hold onto a GRUDGE. Everytime that person comes around, you will find a way to remember what that person did. Especially if it was the ultimate beytral and I understand.
But...holding onto grudges are bad. That are bad because it just sit in your system, and its like a little piece of anger that gets fired up everytime you think about it or when this person come around. It could of happened months or years ago, but you will hold onto that memory like it happened yesterday and thats not good.
Again people piss us off, but the best thing we can do whether they apologize or not is to FORGIVE THEM. I know that hard because they pissed YOU OFF and they should be begging you for Forgiveness...but either way you should let what happened go. I am not saying to FORGET what happened, because it did and that memory will not go away but when you forgive and let the GRUDGE go you will feel better and your life can fully move on.
GRUDGES are a sign of stunted growth. You can expect to grow as a human being knowing that this memory/situation/person eats up at you and pulls you backwards. You get angry, frustrated, cold-hearted, and become a brick wall because of that experience and whether you know it or not, this will effect another situation in the future because you just cant let it go.
Some people are so hard that even when the other person who might of been in the wrong apologizes, its not enough because you just that mad. I will reinstate that I can understand something "seem" unforgiveable, but you can forgive and move on. Be the bigger person and show that this situation was in the past, and let the grudge out of you system.
You can choose to resolve the situation, depending on how sincere the person was with their apology and your relationship prior to the situation (how important were they in your life before this happened) or choose to forgive but not associate yourself with them because you know this person is not "sincere" or can't be trusted (which is understandable).
Everything is about growth, trial and error, who to trust who not to trust, anger & forgiveness, problem & solution and so on and if you cannot go on with life understanding this concept and still want to hold onto GRUDGES then maybe its you with the PROBLEM.
Learn: Be a person who is not weak because they can forgive others, but strong enough to know that people make mistakes. Once you let go of the "grudges" in your life, you can peel away the old you and celebrate another step to maturity and growth.