Every time we ‘remember’ something, we recreate the situation in our mind. In fact, we can recreate and be influenced after the fact so much that we even create false memories. That’s why eyewitness testimonies aren’t as reliable as we think they are; by the time they get to court, they’ve talked to so many people, reimagined the events so many different ways. The way someone questions you can alter your memory so subtly and yet it makes all the difference. We see the past how we want to see it at the time. Mean people become kind, kind people become cruel. Memory is always faulty to some degree, but we can’t operate without it.
That’s why living in the past is so dangerous. Everyone knows people who are bitter. You say one thing and they can’t seem to let it go. Every inconvenience seems to be some large conspiracy against them. Bitter people usually get to that point because they’ve gone over their memories so much, they’ve recreated their entire past to always lead to the present moment of pain. Either everyone else is wrong and forced them into their current state, or they loathe themselves for every action they committed, or some combination of the two.
It’s not wrong to think about the past. You can learn things from history, can take valuable lessons away from events. It also can be a pleasant activity, remembering happier circumstances. I’m not saying we should doubt every memory and try to live like a blank slate; it’s just not healthy to dwell on the past too much. Things change. Our feelings affect what we think happened. If there’s some knot you keep going over in your mind, don’t hate yourself for picking up the rope, get help trying to untie it.