At some point, one has to realize that there are very bad things that can happen that you can control and/or prepare for, and very bad things that can happen that you can't control and/or prepare for. At the end of the day, prepare for what you can, and those things you can't control and prepare for---simply stop worrying, as it is a useless waste of energy and will make your life miserable. Wisdom is knowing the difference between the two.