One thing my three (3) decades of LEO experience taught me is the vast majority of people we encounter do NOT want to harm us in any way. The rest of my life experiences have confirmed that fact.
That said, I will not walk through life with a hand on my gun, always sit with my back to a wall, or otherwise alter my existence in such a way that affects living life fully and happily.
Before anyone chimes in to inquire in what fantasy world I live, let me help you by reminding you my LEO career spanned forty-six (46) states with the majority spent in metropolitan Washington, DC, New York City, and Boston.
I have dealt with many, many bad guys both on-duty and off-duty and my "situational awareness" was keen and remains intact. But, I do NOT consider someone in my path or encountered in any way to be a threat lest other factors are present.
e.g. Last Saturday afternoon I was enjoying some beers in a very crowded bar before the Maryland-Dook basketball game. On one of my myriad trips to the men's room I bumped into many people. One of those was quite obviously carrying a gun. It was on his left hip...concealed, of course. I suspect it was a medium frame autoloader. I quickly noted his attire, body language, and demeanor and continued on my way. Took a moment to spot him when I returned to the bar and instantly determined he was not a threat...to anyone.
Given what has been said (and done) by some herein, what would you have done in the situation I cited? (Kindly spare us: "I wouldn't have been in a bar?"

I was. )
Be safe.