I'm not worried about it at all. I do think a pandemic is more likely than many scenarios. I don't see the corporations letting the financial system going to hell in a handbasket. It's going to limp along, as is government. Things are going good for them, why would they wreck it? Our society is pretty good at denial.
Earthquakes are regional, as are most natural disasters, in general they won't affect me. Major cataclysms are unsurvivable, so, they don't worry me either. Yes, Iran or North Korea could do something stupid. True.
I don't think it is worth living your life devoted to survival of armageddon. Survival of nuclear winter due to a manmade or natural disaster is beyond the scope of what any of us is capable of. I think it is wise to prepare for unforseen occurances to an extent, but I don't lose any sleep over it at all, none. Yes, scientists DO have concern about what returning space craft could potetially bring back. They disinfect and even quarantine. We live on a small planet, and the universe is a very big place. We are really insignificant and our knowledge is very basic.
I enjoy living a sustainable rural lifestyle, so it fits in a bit with 'prepping' which has evolved to be a derogatory term these days. I enjoy being independent. I think it wise to know how to do things the easy way with technology, AND the hard way, like it was done 100 years ago. I think it wise to know how to live without technology, because, as a species, we are fairly vulnerable. History tells us that. Yet, we are resilient, and have thus far, managed to survive as a species. From what I have read, we are all descendent from a group of around 7,000 humans that survived some cataclysm roughly 26,000 years ago.
I am far more likely to die of the excesses of civilization, than I am to die from any other cause. Ice cream will probably cause my demise.