Calibration means your confidence matches your accuracy: when you say you're 70% sure, you're right about 70% of the time. It's a different skill from being knowledgeable, and it's rarer. Most people, including experts, are systematically overconfident — when they say they're 90% certain, they're right maybe 70% of the time.
Calibration is trainable, and the mechanism is unglamorous: make specific, falsifiable predictions with explicit probabilities, write them down before the outcome, and score yourself honestly afterward. Vague predictions ('things will get worse') can't be scored, which is precisely why people prefer them — they protect the ego at the cost of ever learning. The habits that follow are: attach numbers to beliefs, state in advance what would change your mind, treat being wrong as information rather than defeat, and prefer 'I don't know' to a confident guess. The person who says 'I'm about 60% on this' is more useful than the one who's certain and wrong half the time.