You are absolutely right. You should not think about past losses and blame yourself too often, but you should not forget that time either. Why? The fact is that you should know exactly or remember why it happened and make everything so that the next time it was not. Our past actions are an experience from which we must always draw conclusions and move on from these conclusions. The main thing is to always adhere to the basic rules of investing and then you can avoid as much as possible experiences in the future and the present.