Based on blog reports from people featured on the show, they are required to pick only one scenario to announce they are worried about, and many hours of "normal" footage never make it past the editing room. The producers select only the most extreme parts to show.
Even FEMA suggests that everyone be prepared for 3 days without power/transportation/communications, etc. I have heard that they wanted to make it two weeks but thought people would give that up as hopeless, so started with a 3 day supply.
The best way to go about getting prepared (for weather emergencies, natural disasters, man-made crises, etc.) is to first determine what problems are most likely to occur in your area. Then prepare to ride out those. Soon you will notice a lot of cross over. For example, preparing to do without electricity in a winter storm situation will also serve you well if the power goes out due to a terrorist attack on the national power grid. So you find that with minimal additions, you can expand the number of situations for which you are ready.
Also be sure to consider your family and not just go by those FEMA lists. If your kids would literally rather die than eat Spam, then store tuna. When everybody is all stressed out is not the time to fight discipline battles that can be avoided with better preplanning. I think the biggest thing is water. The official recommendation is 1gal/perspn/day. Don't skimp on this. People can live for a long time without food, but only a few short days without water. IMO, the second biggest thing is defense. Everyone's sensibilities are different regarding this - how much force would they use and what kind. As always, one of the best defenses is to avoid the situation, so keep your preparedness status quiet. If no one suspects you have anything, then they won't come begging for it. If it is not in view, then no one will try to...relieve you of it.
And the final "big" deal is to be sure that you have an ample supply of any medications that anyone in your family needs. You don't want to be sitting there, almost at the end of your monthly supply and then have a disaster that wipes out your local pharmacy and destroys the computer systems of others in your area. Often insurers will allow a 30 day override supply specifically for people who might be traveling or in inaccessible areas when their normal supply would run out. Just remember to rotate the meds, replacing your 30 day ration each time a new batch comes in.
There's plenty more to learn about the topic of preparedness and loads of online sites. Watch out, it is easy to get overwhelmed and terribly depressed when reading some of the doom-and-gloom ones. The bottom line is that being prepared doesn't mean that you are living in fear. It means that you are ready, so you don't have to fear.