My father often said that I must either do something perfectly, or dont waste time doing at all, because bad or average result I will get anyway. As well as such result will have others. And I will be like others, I will never succeed. I am not 100% sure that this is that one lesson, but that helped for sure.
The older I get, the more I value knowledge and wisdom of my parents. The older I get, the more I understand how wrong I was and how correct my parents were. However, as I parent, I think I am not ready yet to form, to give or fully understand which lesson I should give to children. But I will try to make my child to understand, that money is an important instrument, but not something to dedicate life to.