Letting go

I have to confess something. I hold grudges. Not over small things like the jerk who cuts you off in traffic, but if you truly hurt me or do something to really tick me off...well, chances are I'm still going to be mad about it in a few months. Or maybe years later. You never know and it could well depend on the severity of the offense. I may never get over it.
As an example, a few years ago my sister-in-law said something to me and I have never forgiven her for it. I can be polite and civil to her, but I don't like her. I spend as little time as possible with her. I dislike her very intensely.
There are other examples but this one has been weighing on me. When my husband and I first started dating I resolved to like his family. When his sister and I were both pregnant I thought we'd be friends. Maybe not best buddies, but at least friends. And now I have no interest in doing any such thing. If I never had to see her that would suit me fine. I don't mind Brian going and developing a relationship with his aunt. Family is, after all, very important. But I don't want anything to do with her.
On the flip side of this is my belief that we should forgive each other. Holding on to anger is a bad thing. It's not healthy (you can look up the studies), it serves no useful purpose, and generally is just a big waste of energy. And most times I can forgive people, and depending on the person I can forgive just about anything. I don't think I'd be married were that not the case. Love is a big factor there, and maybe I didn't have enough time to get to know my sister-in-law well enough to love her enough to really forgive her. I don't really know.
I do know that if some disaster happened and she desperately needed my help then I would give it. I might grumble, but I would help her as much as I could in whatever way I could. But I will never forget what she said to me.
For the record, I have gotten better about letting go of offenses from those nearest and dearest to me. But I'm sure that forgiving someone else has a lot more to do with this unconditional love thing. I'm not so good at that for everyone else yet. Like just about everyone else I have a problem with being a little self-centered. It's hard to put myself in other people's shoes. I want everyone to understand me and my problems and forgive me for my screw ups, but I have a harder time doing that for them. So my project for the foreseeable future, unconditional love. Even for the people I don't like. So that I can start forgiving them.