When I was a child I had a friend who seemed really unpredictable in her moods. She was so much fun to be around, and we made up stories and games together and had many secrets between us. But if she became angry with me, she would make my life hell. She would give me the silent treatment for days, sometimes weeks, at a time. For a child this is like an eternity. But this girl knew how to hold a grudge.
I learned from her, and from others like her, what sorts of people to avoid. I don't like being around people who hold grudges. It's not that I am afraid of their wrath or childish silent treatments, although I do find this behavior tiresome. No, it's more because in those kinds of people there exists a perpetual edginess and anger. Expectations are high, which I don't have time for, but they also seem to be waiting for you to screw up. These people like to blame others for their own unhappiness.
The friend I had as a child eventually grew out of this sort of behavior, but not until she was around 19 or 20 years old. I could see that she was learning how to deal with her anger, and how to see people as fellow humans on their own journey, instead of putting them on pedestals and waiting for them to fall.
It's hard to have people in your life who hold grudges. It seems like such a waste of time. We are here on this earth for awhile, but we don't know how long. We should use our time wisely, and let go of grudges.