I have learned to ignore mine at my own peril.
The Good Lord gave us all instincts about our surroundings and interactions and time and civilization has conspired to dull those senses.
Looking back over the decades, my earlier experiences were much like Gary describes. I came to realize about 20 years ago that had I trusted my instincts more I could have avoided or marginalized a lot of the troubled times, interactions and situations I let myself get corralled into.
Polite society and civilization blunt the sharp end of our natural instincts when we are people who mean and intend no harm to others - we tend to overlook or over compensate to avoid giving offense. But that uncomfortable feeling, that 'inkling', that "spidey sense" is your natural instinct trying to tell you something.
Predators, those of ill will, or folks who simply seek to take advantage prey on that . . . indeed, many of them sense that hesitancy in others and will capitalize on it if given the opportunity.
Personally, I have made an effort to listen to that 'little voice in my head' ( not the one who comes up with all the questionable ideas) and trust my instincts about people, places, and forced situations.
The late, great Col. Cooper acknowledged that living in a constant state of heightened alertness is taxing, can be exhausting, and is not practical except in a combat zone, and that situation/environment comes with its' own set of psychological baggage; but one can train themselves to live in "Condition Yellow" at all times except in the safety of your own home and inner sanctum.
Most of us would be well served to trust our gut more and resist the civilized part of us to over ride those instincts at our peril.