If you want to find a good place to live, just ask people if they trust their neighbors. Levels of social trust vary enormously, but countries with high social trust have happier people, better health, more efficient government, more economic growth, and less fear of crime (regardless of whether actual crime rates are increasing or decreasing).
The opposite of trust is fear. The acid that destroys social happiness is fear. People who promote fear destroy society more effectively than do the people who commit frightful acts. The terrorist terrifies us once - and then we can pull together. The fear monger terrifies us all the time, undermining the very social asset that best helps us build a strong and happy society.