The Shoe Button Complex

I've blogged before about Warren Buffett's super-entertaining, though gargantuan, biography. In it, business partner Charlie Munger and Buffet recall a Harvard classmate sharing with them what he called the "shoe button complex":

"His father commuted daily with the same group of men," Munger said. "One of them had managed to corner the market in shoe buttons - a really small market, but he had it all. He pontificated on every subject, all subjects imaginable. Cornering the market on shoe buttons made him an expert on everything. Warren and I have always sensed it would be a big mistake to behave that way."

This thought occurred to them early on, and it grabbed me immediately. I like this passage because it helps me to reckon with knowing what I don't know. I read it and recall lots of moments in my life, "Oops, I think that was probably a shoe button moment. I didn't really know what I was talking about!"

After a draining day, occasionally my fellow staffers and I re-energize with a game of multiple-choice trivia. Since we make up the questions ourselves, it quickly becomes clear that we all have a lot of niche knowledge. The look of dread hits my face when they start asking me about rodeos, sports, and presidential history. I just don't know that stuff (yet?). So even through my losing streaks, I usually leave with a smile, "Now I know a little more about what I don't know!"

Question: what do you know, and what don't you?