mistakes in the past being the best teacher, an experience that should really make us able to avoid the same problem. It takes several tries to avoid the same problem, every trader has their own strategy, but what is certain is that avoiding losses is something that must be done. We also have to have control over the trades that are being made, lest the traders only get losses.
Making losses is fine, not letting them get to us is the real treasure in the trash. If we could keep our heads high and keep on doing something that is profitable for the future, then we will be fine. Those losses should become our school books, we should be able to learn from them so well that in the future when we are about to make a mistake, we should remember the mistakes we did in the past and avoid doing them again.
This isn't hard, sometimes you make the same mistake two or three times or even maybe more before you learn to avoid them. But as long as you learn, and you do not make it again, they are still our lessons and they are valuable.