I'm pretty much a worrier. When I am going to do something, I think in advance of every possible thing that could go wrong and try to think of a counter-strategy. This mostly serves me well, but it has two major flaws. The first flaw is that it can take a lot of time to think of 'everything that could go wrong', leading to analysis paralysis and the general feeling that it's not worth doing anyway because so many things could go wrong. The second flaw is that I can be completely blind-sided by something I didn't anticipate in my plans. The first flaw happens to me a lot more often than the second. In fact, I usually end up preparing for situations that never happen, thereby wasting a bit of my time. For someone who doesn't like insurance I sure end up insuring my own actions a lot.
Other people are the complete opposite. Of the set of all possible problems that could occur, they perceive (or choose to perceive) nothing. Whatever comes their way, they will deal with it if it arrives. This tactic works great if a lot of small things could go wrong that could be easily fixed, but fails when there are some major problems that cannot be dealt with ad-hoc.
Most people are somewhere in the middle of the spectrum, I'd guess, although I do know a couple of them that are rather extreme. I can't help but become frustrated when that happens, but that's just in my personality. I like to play it safe and make contingency plans. Other people smash through life like a hammer. Let's try to be understanding of each other and perhaps nothing will break.