My wife accuses me of being a pessimist.I say, everything bad that has ever happened to me (and, objectively, not much has) has been unexpected. The theory, therefore, is that if I worry about everything that can possibly go wrong, nothing will.
The flaw is that there are an infinite number of things that can go wrong, and a finite amount of time to worry in. But I try. My wife says I'm very trying, as a matter of fact.
Peter