...is that theoretical convincingness doesn't mean it actually works.

I was reading The Inner Game of Tennis by Timothy Gallwey. It's a classic for good reason. There's many brilliant ideas and insights in the book, directly applicable to living a better life.

And he speaks from a place of totality about how relaxation and nonjudgmental behavior towards yourself produces better outcomes.

It's thoroughly convincing. But then I realized, wait, that's not necessarily empirically true.

Specifically, another book on tennis came to mind -- Open: An Autobiography, by former world #1 Andre Agassi.

Agassi's training methods under his father and under his own judgment were the polar opposite of Gallwey's recommendations. Now, Gallwey is smart. The Inner Game is a classic for a reason. And it probably leads to happiness. The trouble is, his arguments will have you nodding in near universal agreement, despite having many potential exceptions and caveats. Convincing arguments can be troubling like that.