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 being particularly dark.
Example: you know what would be harder than anything we're talking about here? Quadrupling the performance of the best compression algorithms. It's hard. In fact, maybe there's some information theory that even says it's mathematically impossible. That makes it really hard, which makes it what all of us should immediately start working on.
The author writes elsewhere that you also have to have an edge, but that's frequently omitted from this "hardest thing" advice.
I think it's supposed to be interpreted as 'the hardest thing on your list of possible startup ideas', not 'the hardest possible thing in the universe'. I think it's also an alternative way of thinking about a moat.
Yeah, this type of advice rubs me the wrong way: I feel like the author is thinking of "hard" as though it were back-breaking day labor that any fool could do, but nobody wants to because it's so unpleasant.
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"?
Yeah I feel like this advice kind of reminds me of a lot of advice - you could rewrite it like "Do the hardest thing -- by which I mean, not the easiest thing, and not the actual hardest thing, but the thing with the right amount of hardness, a narrow band somewhere in the vast middle that you'll only be able to recognize once you have enough experience that you no longer need this advice."