2 or 3 years ago I decided to slowly build up a 6 month supply of 25 year shelf life emergency food, enough for 3 -4 adults. My wife thought I was going a bit over the edge but I convinced her it's better to have it and not need it than need it and not have it - she agreed. I have a 14 cu. ft. upright freezer that is packed full of meats, vegi's, butter, etc..., plus I have quite a store of dry goods such as pasta, jarred sauce, canned vegi's, canned meats, tuna, sardines, rice, dried beans, etc.... I'm not a clairvoyant and only had about 30% on-hand of what I felt was needed of these items prior to the SHTF. I did kind of see the handwriting on the wall and started to accumulate more of the basic staples as well as items of "higher" value, such as TP, before the run on these items began. I was in pretty good shape when the lines were out the door and around the corner, so to speak, at most places.
My parents had a "bomb shelter" style food pantry down in the basement of our home when I was growing up in the age of the US/USSR MAD "agreement". Fun times were had for all! I've always stock piled items that I felt were important. Why buy one or two when you can buy 3 or 4 and save it for later, "just in case". This was true for food, ammo, firearms, self defense weapons, TP, H2O (even though I'm on a well), generator, spare fuel and the list goes on. I lucked out with N95 masks from previous woodworking projects and had about 75, some of which I doled out to family members in critical jobs or compromised health conditions. I also had a couple hundred heavy duty black rubber gloves that I had bought for oil changes and mechanical fixes on my power equipment. Never thought both would become as valuable as they did - who knew?
Lack of food, IMO, would be the major reason for a breakdown of societal norms and lead to riots, looting, etc... I'm planning on sitting tight in a defensive position as long as possible should this happen. I'm in a fairly rural area and can't see "bugging out" from a good, defensive position with plenty of water, food, ammo and manpower. I really hope it never comes to that!