A natural or subtly theatrical show of your situational awareness can act as an incidental preventative form of passive self-defense.
Organized terrorist operations require extensive research and planning, which develops into discernible patterns that can be detected before the act.
As a constantly revolving foreigner, the art of haggling is a most useful skill to master for necessity and practicality. A skill also valuable back at home.
A most careless action is underestimating another person and using that to needlessly antagonize a potentially dangerous foe.
It’s arguable that being street smart is better than book smart on a general level, but as a foreigner traveling abroad, the former is.