Stop for a second, and if you have a piece of scrap paper handy, wad it up, then toss it in the trash can from 5-6 feet away. In an instant our brain calculates weight, mass, size, wind, aerodynamics, obstacles, distance, and compiles that so we can make an accurate shot. You might have gotten the paper into the trash can, you may not, but the brain’s ability to analyze all that data is still the same.
The same thing happens for wedding photography, only the parameters are different. True, past experience plays a large role, but there are still hundreds of computations taking place in a split second. There are the technical details such as camera settings, compositional decisions on how the photo should look, along with the photographer’s own secret sauce that gives it his style.
Some of the decision are made ahead of time, but as conditions change those variables are taken into consideration and re-evaluated to ensure the photo (wad of paper), comes out perfect (goes in the trash can).
Or it could be that we just lift the camera up to our eye and press the shutter release.