Every man has just as much vanity as he wants understanding.

Self-importance tends to fill the space where judgement is missing. The less someone grasps a subject, the less they can see of what they do not know, so their confidence has nothing to push against. Real understanding is humbling in a specific way: it shows you the size of the territory. This is why the most certain voice in a room is so often the least informed one.

Treat your own certainty as a thing to check rather than a feeling to trust. Where you are most sure, go and find the person who knows more and ask them a genuine question.