We, along with a vast majority of the animals, have an acute sense of our surroundings. 

We can tell when someone else's voice or their behaviour is off and end up inquiring if they're feeling alright. We can tell if there's an unexpected change in the quality of air, brightness of light, etc.

Evolution has favoured those who have this sense of their surroundings, as it has enabled them to survive and navigate it better.

I've started to think of expertise in an area or domain in a similar manner.

A sign of expertise is to have this sense to say if something is wrong or off at the slightest signal from the environment. 

Great product managers have this sense for how their customers use their products, great engineers have this sense for how systems perform, great salespeople have this sense for how people make purchase decisions. 

Are you happy with your ability to spot things that are off in your domain?