What to Learn
I believe the thing we often need to learn is the thing we're afraid of learning. We often (always?) have weaknesses that can/do jeopardize our strength and closing those weaknesses is crucial.The famous Scott Galloway (whom I had as a b-school professor) made this point like this: if you are a great guy, great father, great boss, etc, but once in a while you get violently drunk and hurt people in your life - THAT thing offsets everything else. You won't become better by "doubling down" on what you're already good at, but by fixing this flaw.Another case - I used to manage a C++ developer. If you gave him a tight spec, he'd implement it perfectly. But the world we lived in required him to go talk to people to figure out what the real needs are, and he was bad at that. So his code always solved the wrong problem unless someone was helping him with this stuff.Every year, his own developmental goal was to go learn the next C++ standard. And that would have been useless because he was already a great C++ programmer. Going from 97th percentile to the 98th wouldn't matter. The much bigger bang for the buck would be figuring out how to go sit down with a sales rep and say "OK, what's our client actually trying to do here?"It sounds simple but I believe this held him back not just in work but in life. I happen to know that he didn't have great communication with his wife and kids either - solving this thing would make him so much better at all parts of his life.The thing is - we all have glaring things like this - obstacles in our own trajectory that if we fix, our existing strength would really shine.