Health is mostly invisible until it isn't. You climbed stairs this morning without negotiating with your knees, and you'll forget you did.
That forgetting is a strange kind of luxury. A body working well is a body you don't have to think about, which means the gratitude has to be deliberate — nothing about feeling fine reminds you to feel thankful.
And health is rarely total. Most people are grateful for the parts that work while managing the parts that don't. Both can be true at once.
Notice one thing your body did today without asking you first.