It's just like driving the car. Difficult to focus at the begging but once you practice for some months it feels quite natural. The next level is driving the interview to expose deception and that's a nightmare since you need a super high level of self control.

Its interesting what traits drive this skill.

I am fairly intelligent, and consider myself emphatic and not unintelligent emotionally, but I just can't spot lies. By default I assume people are telling the truth and can't seem to override this setting in my brain.