Those take the form of intrusive thoughts about the past which haunt us. The bottom line on that is that those drain our energy. In addition, they can take a toll on our confidence.
Fortunately, there are many tools for ghostbusting.
One is practicing mindfulness or meditation. If we stick with it, that can rewire our brain.
Since meditation has gone mainstream, training widely available and usually free or low-cost. Local versions of publications such as the free Natural Awakenings list where we can pop in and learn the ropes. It can be helpful to meditate with a group. That is also available for free at centers for healing such as Buddhist temples.
Another tool is relocation. Sometimes by leaving the "scene of the crime," we can regroup. A couple caught up in a business failure on the East Coast moved out west. It really did provide a new start. Their confidence returned. They didn't encourage anyone from the past to contact them.
A third tool is simply to get it that regret is nothing but a fantasy about what could have played out. We may be preoccupied that we should have done this or had said that. Yet, we have no way of knowing how those choices would have worked out.
One ghost chasing me was my shame about the self-defeating person I had been in college. To derail that freight train running through my head I made a smart move: I purged former classmates from my Facebook page and life.
Among them were Kathleen Huebner and Irene Nunn. That was May 2014. Haven't had the dark night of the soul since. In addition, my communications boutique has had a roaring comeback.