I was falling into the “second group” Steven talks about for a while there. Now I just want to go back in time and smack myself (classic overconfidence of a novice). I will still happily discuss what I’ve learned with anyone who’s interested, I’ve just become much less eager to do so. I’m much more content sticking to applying and optimizing what I know to me.
I have also noticed that as my understanding has broadened and deepened, my confidence that my understanding is complete has gone down significantly. I gather this is just better knowing what I don’t know, but it’s not all bad. It’s helped me to be more cautious and extremely critical of “new” information, which leads me to fully understand new things before integrating them into what I already know.