Productive people learn from the past, but they don't dwell on the past. The problem many unproductive people have is they try something, they fail. And now their image of themselves is I'm a failure. I can't do that I got to stay in my lane. I can't venture over there. This is outside my skill set, wrong mentality to have if you want to be productive and successful.
Now, if you never reflect on the past, then you are doomed to keep repeating past mistakes and you get nowhere. That's not good. You want to learn from your mistakes, assess your mistakes, but you want to be analytical about and figure out what did you do and not do? What did you do that caused problems so you can make sure not to do that? What did you do that caused partial success so you can do more of that. That's what successful people do and no matter how many failures they have, they don't label them.
Sells the failure. They say this particular action fail this particular venture fail the second you call yourself a failure. Then why start anything new? Why attempted because if you're inherently a failure, you're going to fail at everything. That is your essence. That's your character.
Productive people don't get mired in that negativity. So the past is important. You don't want to instantly Forget it. But you want to learn lessons that will help you in the future, not bind you and control you.