Closure?

Something has been nagging me lately. I'm pretty good at not holding grudges, letting things go, etc. I mean, just like everyone else, a lot of things happen in the course of my relationships that I don't like. Sometimes I do react, especially if the hurt/anger is instant. More often than not, I internalize, mull over it for awhile and then either let it go or hold onto it for a little longer, rinse & repeat, etc. Generally, I try to consider the value of saying something. Will it change the situation? Usually not. Will it make things worse? A lot of the time. Will I feel better? Maybe for a minute.

Said process hasn't worked on what's currently nagging me. I can't let the issue go and I haven't said anything to the person and what's worse, I can't decide if I want to say something or not. The relationship has ended. It will never resume. So there's nothing to salvage. I don't care what the person thinks of me and while I wouldn't intentionally hurt their feelings, if that happens, I won't lose any sleep over it. The only reason to say anything at this point is so I can move on and be done with it. I guess that's called closure, right? I know a lot of people are all about closure, moving on, yada yada. It's never done much for me. But, I'm feeling it in this situation...

Are there negative side effects to closure?