Security expert Bruce Schneier has an insightful understanding of terrorism, fear and reaction:

The real point of terrorism is not the act itself, but our reaction to the act.  And we are doing exactly want the terrorists want…The implausible plots and false alarms actually hurt us in two ways. Not only do they increase the level of fear, but they also waste time and resources that could be better spent fighting the real threats and increasing actual security…The surest defense against terrorism is to refuse to be terrorized. Our job is to recognize that terrorism is just one of the risks we face, and not a particularly common one at that. And our job is to fight those politicians who use fear as an excuse to take away our liberties and promote security theater that wastes money and doesn’t make us any safer.