I probably interpret the message incorrectly, because to me "the hardest thing" is usually some class of some famous unsolved problem. The thing is, to be famously unsolved, many of the world's most brilliant people must have already tried and failed to solve it. There's a chance I have an edge they don't, but it's probably not wise to track your career path to the darkest of dead ends purely on the merits of it bein…
The sort of people it's usually directed at, though, are knowledge workers (like computer programmers). "Hard" in our context is "something I don't yet know how to do". Always. No exceptions. Every time. If I know how to do it, it's trivial. If I don't, I have to figure it out.
And in my experience, the "do the hardest thing" VC-founder cheerleader types (who are always telling you, never themselves) absolutely lose their shit when they see somebody trying to figure out how to do something. Reading docs? Setting up controlled experiments? Why are you wasting time with all of this nonsense and not just getting to the "hardest thing" so I can bill the client and you can move on to the next "hardest thing"?