We spend an awful lot of money trying to feel better. Supplements. Apps. Fitness trackers. Meditation subscriptions. Massages. Cold plunges—which are also a fantastic place to practice intentional breathing. Fancy mattresses. Red-light therapy mats, stands, and gadgets. Vibration plates and cupping devices for lymphatic drainage. All sorts of things promising better sleep, less stress, improved focus, lower blood pressure, and a calmer nervous system. And meanwhile, one of th