I have to piggyback on @elbanditoroso‘s answer.The first 2 years in my field I struggled to master different aspects of my job in fear that someone would discover I didn’t know what I was doing. I guess I must have succeeded because I gradually began getting visits to my desk from co-workers needing assistance. I even got a verbal reprimand for receiving too many visits to my desk, but I rarely turned away requests for help. Most startling was receiving occasional out of state requests via phone or email. (Amazing how your work performance gets around…!)
Eventually I was requested to mentor. Quite intimidating because I feared I would learn from my peers I still had much more to learn. This proved to not be the case. In fact, it became quickly apparent that other employees selected to mentor and teach weren’t qualified to do either. I participated in several awkward meetings with managers trying to explain why I believed students were being taught erroneous information. That is, after being reprimanded for advising students with procedure that contradicted what was taught in class.
I eventually taught classes myself. I’ve since lost whatever enthusiasm I had for mentoring upon realizing my organization was more interested in simply documenting employees were being trained instead of ensuring the training received was being accurately applied to the work at hand.
At present, I’m resisting pleas from management to teach an upcoming class as I’m the only one they feel confident enough to teach our new employees. They probably should have thought of that when I was pleading with them to stop the practice of allowing unqualified students to pass and to begin monitoring the quality of work performed. They ignored me, so they have a staff full of incompetent employees, and no one (but me, apparently) qualified to train new employees.
Anyway, that’s why I feel I’m an expert at my job.