Scythe, it's been a combination of things rather than 1 individual reason.
My main worry is storing food incase I get made redundant at work. If it happened, we might not be able to afford essentials such as food so having a store seems like common sense to me. I also worry about a spell of bad weather & the shops not being able to supply us. I had an experience a couple of years ago where we did our shopping online & the van couldn't deliver it because they were snowed in. We had some food in the house but were running low on essentials like bread & milk, packed lunch items. I had to drive 9 miles there & 9 back on icy roads to collect the shopping. Skidding around the road because the council idiots hadnt been out with the gritters isn't a nice experience, I can promise you that.
However since joining this & similar sites & seeing what is happening in the world (eurozone crisis, mass immigration, food shortages & price increases) its opened my eyes to other things & I don't want to get caught short.
I read a series of interviews from a Bosnian caught up during Balkans war (
http://www.shtfschool.com if anyone fancies a read) & quite frankly it scared me. Women trading sex for tins of food, people being killed trying to find food for their family, people dying from infections in simple cuts. Plus I want to put off eating rat or grass pancakes as long as possible, for me & my family.
A little bit of effort now can put off a whole lot of suffering later on if anything bad was to happen.
Hope this answers your question.