"Truth—or, more precisely, an accurate understanding of reality—is the essential foundation for any good outcome."
This makes sense. Without knowing where you're starting, it's impossible to know what you need to do to get where you're trying to go. You can drop a pin on your goal, but if you don't know how far away you are or in what direction you need to move, well, you're screwed.
But Dalio expands upon this point with something I don't agree with. He writes, "...it is more important to understand and deal with the bad stuff since the good stuff will take care of itself."
I don't buy this. Sure, weaknesses must be admitted. And yes, fooling yourself into thinking you're good at something that you're bad at is valueless at best. But understanding strengths and learning to maintain and enhance them can often provide more value.
Let's bring this back to Post 1:
A Minor Leaguer would be best suited to take an honest look at his current skills compared to Big League average, and then decide to invest in aggressive training in an attempt to close the gap.
We'll look at a made-up player with the following toolset:
Run - 30
Arm - 30
Hit - 50
Power - 50
This player will likely never be an average runner or have an average arm. He should work on these skills, but they're not the ones getting him to the Big Leagues. Instead, this player should realize that if he's going to make it, he's going to have to be an average fielder with a plus hit tool and serious pop. In other words, he needs to turn his average tools into plus tools.
I think this applies to many other areas of life. If you're a good communicator, work to be a great communicator. If you're a good computer programmer, go become Linus Torvalds. Try to make sure you're not brutal at anything, but instead of being average across the board, take a realistic look at the world and then figure out where you have the potential to be great.