If this is the only thing I accomplish today, will I be satisfied with my day? - Tim Ferriss

Sparta, Rome, the knights of Europe, the samurai . . . worshipped strength. Because it is strength that makes all other values possible.

The immediate answer that comes to mind is ‘humility.’ Because you’ve got to be humble, and you’ve got to be coachable. . . . Later, when I was running training, we would fire a couple leaders from every SEAL Team because they couldn’t lead. And 99.9% of the time, it wasn’t a question of their ability to shoot a weapon, it wasn’t because they weren’t in good physical shape, it wasn’t because they were unsafe. It was almost always a question of their ability to listen, open their mind, and see that, maybe, there’s a better way to do things. That is from a lack of humility. . .

If you spend your time, worth $20-25 per hour, doing something that someone else will do for $10 per hour, it's simply a poor use of resources.