For centuries astronomers couldn't get the math to work. They kept adjusting the orbits, adding correction after correction, and the model still fell apart — because nobody thought to question what was sitting at the center. A lot of us are doing the same thing with our lives.
Psalm 16 is a song David wrote while his life was in real danger, and it makes a claim about what belongs at the center of a human life. Whatever you put there sets the orbit of everything else — your marriage, your kids, your work, the way you see yourself and other people. Put the wrong thing there and life starts to wobble, so you add more control, more effort, more coping, and it still never quite sits right. David gives three reasons God belongs at the center: He is our greatest good, our greatest help, and our greatest joy. Then comes the catch — you can't re-center your own life by trying harder. Something has to move in and take that place.