I am a natural worrier, and so there are times, where I wish I was more prepared, in the sense of having supplies at home, a generator, a way to generate hit during an ice storm. And in the general sense, of wishing wasn't dependent on stock market, regular job for income, was more self-sufficient.
The truth of it, if it is a true doomsday scenario (like the black plague in the middle ages, swine flu in the early 1900's, being caught in a war, ditto huge natural disaster or what we are doing, the degradation and unbalancing of climate, nature) there is actually rather limited things you can individually do. Sure a certain percentage of the human population will survive (those in rural areas, preppers, those who are simply lucky in where they are in time and place) but I don't think there is any way to guarantee that you personally will survive, as well as big impacts to certain populations and our society, civilization.
i think it is common sense to prepare for what are pretty common events such as power outages, flooding, etc with supplies, escape plan, etc. But for events that are expected to last weeks, months, years, that really means planning your life around that these potential events occur, and not going to do that.