As others have mentioned, many people find distraction helpful. I, however, find that sometimes the regret/thought is so compelling that distraction just doesn’t work. And more importantly, distraction seems to put off the thought until a later date, when it will appear stronger and more real the next time.
I find a few things helpful in this area. They may or may not be helpful for you. I find that truly understanding what a regret is helps. A regret is a current thought about the past. It is fueled by simulations that play out events as you imagine they would have happened if you had chosen differently. It seems we have evolved so that our minds simulate the past and future to aid in decision making and risk assessment. But in my experience, we believe these simulations/fantasies far too much. In reality, we’re pretty awful at predicting what will happen next. And to believe that we can predict the chain of events that would have occurred if we had only chosen differently is pure fantasy and delusion. We all do this.
I find that if I understand that these scenarios playing in my head are completely natural, it’s what the mind does, than I can not take them as seriously. I don’t have to believe them. There are far too many variables in reality to assume that we can direct a movie in our heads that would remotely reflect reality.
There’s also the fact that I chose to do what I chose to do. Did I have another option in the purest sense? I don’t believe so. (This is where you can skip if you find deterministic rejections of free will insane). I can’t choose the next thought that will appear in my mind right now. In fact, if I look at the simplest of decisions (pick a number between 1 and 3, for example), any explanation of why I chose what I did is pure rationalization. I only become aware of my decision once I have already decided. Neuroimaging experiments can even see a decision seconds before we are aware of them. But these experiments aside – if I am in no position to know why I chose 1, and not 2 or 3, I certainly am in no position to know why I make more complicated life decisions. In a strange way, there is something comforting about this. If I could not have chosen otherwise, then it makes little sense to regret my decision.
And related to the “if I had chosen differently” simulations that our brains run, we seem to be good at building models that would keep all of the good stuff from our current reality, while accumulating all of the benefits that would presumably come from having made a different decision. For example, in previous regretful moments of my life, I conveniently fail to account for the fact that had I not made a specific decision, I most certainly would not have met my wife and had 3 beautiful kids.
So I don’t use distraction as much as looking more closely at the nature of my regret, what fuels it, and how delusional it really is.