Most of us over the age of five have had arguments. We've all had the moment after an argument sitting pondering each word that was said. We reflect on the pain, the anger and suppress the urge to go back and fight more. As you sit there and calm down a bit you think of all the things that you could have said. You wonder why it never occurred to you to say it before. You curse yourself, but your head was clouded with fury or sadness. There was no way that you could have thought clearly enough to say those things and if you did would you not have regretted them later as you reflected.
Often there are things that we long to say or wish it was said. However, most of that is discarded by the wayside during the day to day. Some of it is bottled up inside waiting for that one moment when you explode.Then there are those times when you only think of it when you simply have nothing else to do. You relive the argument over and over again in your head each time thinking of more and more things you could have said. Some times the anger may boil over and if you still encounter the person then there is a bit of resentment. Some times you have no contact with that person and all you want is one more chance to go at them. That little person in the back of your mind tells you that it is pointless and nothing will come of it. The little devil on you shoulder tells you that it will make a difference and helps you scheme an encounter. In the end you sit alone wishing for a chance that you know in the end wouldn't turn out the way that you expected.
Case in point. In a relationship past, we argued. After each argument I would sit there hurt and pissed to the point of no return. After the tears would subside and the anger would be less intense there would be so many comments and insults popping into my head that I longed to say. I would stew for hours afterwards knowing the things I should have said never made it past my lips. Even after the demise of our relationship I would find myself occasionally wishing that I would have said those comments. There were some days after where I wished I could have run into him again just to let him know just what I thought of him. Then I realized it wouldn't matter. Even if I had said those things nothing would have changed. It wouldn't have made me feel better. It wouldn't even have gave me a hint of satisfaction. So what did I do after this sudden realization? I used the knowledge to help me grow as a person.
Although it can be really tough the best thing to do is let it go. Find a way to release the tension and make peace with what was done. Talk to someone about it. Write your feelings out in a journal. Take up a new activity. Whatever way works for you because keeping it in will only end badly. Then once you do that learn from the experience.