Think of a decision that you regret.
If you’re having trouble with this, you’re not alone. We as humans tend to remember the good memories and forget the bad. As this article suggests, our brains will either suppress or substitute this bad memory by moving it to a different part of the brain.
Note that we’re talking about the less intrusive bad memories. The destructive memories, like those that cause conditions like PTSD, can be incapacitating and don’t apply here.
But still, c’mon brain! Don’t they say that we learn from our mistakes? Imagine if we kept those bad memories and we learned from them. Would we advance faster? Make better decisions? Would close-calls impact our behavior for a life-time rather than a few months?