Determination & Relentlessness

From How To Work Hard

What I've learned since I was a kid is how to work toward goals that are neither clearly defined nor externally imposed. You'll probably have to learn both if you want to do really great things.
The most basic level of which is simply to feel you should be working without anyone telling you to. Now, when I'm not working hard, alarm bells go off. I can't be sure I'm getting anywhere when I'm working hard, but I can be sure I'm getting nowhere when I'm not, and it feels awful.
There wasn't a single point when I learned this. Like most little kids, I enjoyed the feeling of achievement when I learned or did something new. As I grew older, this morphed into a feeling of disgust when I wasn't achieving anything. The one precisely dateable landmark I have is when I stopped watching TV, at age 13. Several people I've talked to remember getting serious about work around this age. When I asked Patrick Collison when he started to find idleness distasteful, he said
I think around age 13 or 14. I have a clear memory from around then of sitting in the sitting room, staring outside, and wondering why I was wasting my summer holiday.
Perhaps something changes at adolescence. That would make sense.
The best test of whether it's worthwhile to work on something is whether you find it interesting. That may sound like a dangerously subjective measure, but it's probably the most accurate one you're going to get. You're the one working on the stuff. Who's in a better position than you to judge whether it's important, and what's a better predictor of its importance than whether it's interesting?
For this test to work, though, you have to be honest with yourself. Indeed, that's the most striking thing about the whole question of working hard: how at each point it depends on being honest with yourself.
Working hard is not just a dial you turn up to 11. It's a complicated, dynamic system that has to be tuned just right at each point. You have to understand the shape of real work, see clearly what kind you're best suited for, aim as close to the true core of it as you can, accurately judge at each moment both what you're capable of and how you're doing, and put in as many hours each day as you can without harming the quality of the result. This network is too complicated to trick. But if you're consistently honest and clear-sighted, it will automatically assume an optimal shape, and you'll be productive in a way few people are.

From The Anatomy of Determination

In most domains, talent is overrated compared to determination…After a while, determination starts to look like talent.
I cannot think of any field in which determination is overrated.
The simplest form of determination is sheer willfulness. When you want something, you must have it, no matter what. A good deal of willfulness must be inborn because it's common to see families where one sibling has much more of it than another. I don't think there's much you can do to make a weak-willed person, stronger-willed.
Being strong-willed is not enough. You also have to be hard on yourself. Someone who was strong-willed but self-indulgent would not be called determined. Determination implies your willfulness is balanced by discipline.
That word balance is a significant one.
The stronger your will, the less anyone will be able to argue with you except yourself, and someone has to argue with you, because everyone has base impulses. And if you have more will than discipline, you will just give into them.
The more willful you are, the more dangerous it is to be undisciplined.

From Relentlessly Resourceful

This is one of those ideas that once it gets in your head, it never let you go. I finally got a good startup founder down to just two words: relentlessly resourceful.
Till then the best I'd manage was to get the opposite quality, hapless. Hapless implies passivity. To be hapless is to be battered by circumstances, to let the world have its way with you, instead of you having your way with the world.