If you do it right, you'll reach a simmering intensity of awareness. You're eyes pick up on everything that moves within 80ft of you. There isn't a thought in your head but, at the same time, you see and hear everything. The substrate, coral, mangroves, jellies, rays, crabs, birds, clouds, winds, shadows and hopefully, fish. You engage auto pilot, plugged in to this web of life, and become a predator.
Hours may pass without notice. When you see a fish, (somehow your brain indicates immediately that the shape and shadow that looks identical to the hundred other similarly shaped shadows around you is not a bottom feature, it is alive.) your body reacts. Choreographed hands manage line and somehow you can drop a fly in the right spot, at the right distance, at the right moment. Activating the fly, you become the prey.
The fish might look, it might not. It might follow, it might turn and run. If it eats, you're ushered from the trance by the particular song of whatever reel you're holding on to. You know it by heart.
It is probably a bonefish, but it could be almost anything. Sharks, barjacks, tarpon. The diversity of life in these waters provides a feeling that is the opposite of the universal fear of the unknown: the anticipation of the unknown. If it is a bonefish, you can prepare to see your backing, as they are fast. If it is a horse-eyed jack, you can prepare to fight to keep your backing, as they are insane.
There is always the glimmer of hope that you'll see a sickle-shaped tail. A permit. The holy grail. If the right fish swims by, you'll be ready.
Your brain bathes in endorphins from the moment you strip line off until you return to the shores. It seems to relish the hunt, as though you're finally using it for what it is best at.