This is a great article at SurvivalBlog.
The average human brain can't handle much reality. It often seems as though each person can only grasp a portion of what it is that is being talked about when TEOTWAWKI is mentioned.
I'm sure you've seen all the people described in this list. It's probably a result of growing up in such easy times. Everybody hyper focuses on a single element to the exclusion of all else. They have a failure of imagination.
You need faith, air, water, food, shelter, light, security and hope. It's best to work on them in that order.
Sometimes you hear people on the internet fantasizing about how because they have a gun, they will just take what they need in a crisis. Or their kung-fu skills will preserve them in the wasteland. These fellows will be lucky to survive ten minutes after TSHTF. Or the guy who insists his gold coins will buy him whatever he needs when the time comes. Or the woman who claims that discovering our inner chakras will protect us. Or the person who says whatever happens, they won't want to live anyway. All of these people have made a clean break with reality at some point. None of that is realistic.