They taught me three important lessons about personal finance: always save your money in a reserve account; always live below your means; and never get too deep in debt.
I have seen good times and I have seen some hard times. Saving has been so important, especially when I have been forced to live off tuna and pasta.
Living below my means is sometimes a challenge, but it is related to the first lesson because one must save and be ready for the hard times that are sure to come.