I can only think of one female active on the Saints board, do you really want to be locked in a bunker with her?

I'll wait outside and embrace the impending doom thanks.

these people always assume they'll be the ones that aren't turned into zombies in the scrambled scenes cut with news footage at the beginning of every zombie film, or the ones crushed by a falling tree in the 'freak weather hits east coast' news articles at the beginning of every natural disaster film

Having watched a few episodes, I think that they are people, for whatever reason, who do not like or cannot cope with the modern world. The hoard goods and food in the hope that they are proved 'right' and the modern world is washed away. In years gone by, they would have been evangelicals taking about the end of the world and praying morning noon and night for our sins.

It's all very well hoarding food, but it wouldn't have been much of a doomsday if Sainsbury's was open again after 3 months so what do you do then?

Hoarding seeds, roots, etc and gardening/farming implements would be the answer. Of course you also need a bit of land, preferably hidden. But if there's a nuclear winter as a result of a meteor strike, supervolcano or indeed nuclear war, you're screwed.

One person could hoard food to last a few years if they so desired - many tinned foods will last up to 3 years, dried food often 2 years. Bottled water, pop, etc will keep for over a year.

It's always worth keeping a few essentials around just in case of long-term power cuts, but 'preppers' seem to be people secretly hoping for some global disaster so they can demonstrate their superior resilience, survival skills and get back to basics by eating from giant tubs of refried beans.