Going back to the OP, I think the best example of failing to learn from our mistakes is hard drug addiction, which we have known for decades/centuries is no good, yet exists in society at higher rates among the general public than ever before. Its like, we know things are bad, and we do them anyway, because we're basically monkeys.
As you have said being a dumb can just sometimes be a human nature, no matter how smart the person is. We tend to do things based on our emotions and a good example is what you have said drug addiction. It is bad and illegal substance that can destroy our body yet there are still some people who gets addicted to it why? cause it feels good.
Aside from that this substance has chemicals that can ruin our mindset that makes as dumb