Are you an expert in your field? Wonderful! Now be careful.
In a recent study, Stav Atir and colleagues reported that self-perceived expertise can lead to people overestimating what they know and may even lead some to claim they know all about stuff that is real - bogus topics. The phenomenon studied is called overclaiming, which is a situation in which a person overclaims what they know about their own area of expertise. During the studies, people who self-identified as experts in financial concepts were asked to rate their level of knowledge about real and bogus financial topics. The "experts" claimed to have knowledge about the real and the bogus topics, even when they were warned that some of the topics listed were not real.
So, if you're an expert, be careful of claiming what you know. Make sure you really do know what you're being asked about. It could be someone testing this claim.