I have seen some articles about the psychological impact of the news media on people. It seems the more people watch news stories about violent crime, terrorism, etc., the more they overestimate the likelihood they will be involved in such an event and underestimate more statistically tangible threats, like being killed in a car accident or an accident at home.
Just a little reality check about the situation described at the Wal-Mart: There have been a number of posts talking about middle-eaterners acting funny at various places, but none have ever resulted in any incidents, other than posters going all "Condition Red". In fact, there have been no terrorist incidents on U.S. soil since 9/11. Incidentally, these terrorists usually go through all sorts of cleansing rituals before they due their suicidal thing, and I doubt you are going to find one of them blaspheming their religion by singing along with Christmas caroles right before they martyr themselves. Might piss off Allah under their rule book.
You're in much greater danger in the Wal-Mart parking lot from the little old ladies who can't see, and the idiots talking on the cell phone as they drive.