For anyone who has read much of LTC Jeff Cooper’s writings, he would term it being in Condition Yellow. You don’t want to stumble through life in Condition White, completely oblivious.
Scroll down a little more than halfway to see one of his expositions on the subject.
http://dvc.org.uk/jeff/jeff13_1.html
On a more local note, we have Squantos’ long time tagline, that he doesn’t seem to be using at the moment, which should be brought up in the context of this thread:
Be polite, be professional, but have a plan to kill everyone you meet.
A few pings.
Fully concur. Love the tag line