There never was. In the early 20th century people were scared of Nihilist bombers. In the 16th century the fear figure was the "murder-burner", the arsonist. (In cities of tarred wood and thatched roofs you didn't need a bomb to create a massacre, just a torch.) Greek and Norse legends include tales of people who were possessed by gods or demons and ran wild killing everyone in sight. There is a minute but real possibility that the next person you meet will be looking to kill you, for political or religious or psychiatric reasons. You either live with it, or stay home and hide under the bed.