I think as we get older, we start calculating right from the minute we see the deer. How much time do I have? Can I move without being seen ? Does it have horns, and how big ? How far do I let him go ? Everything runs through our heads, we calculate, we act, get ready, and make the shot. When I was younger, I was like a balloon filled with air, then... let go , pppphhhhhhtttt. No thought, just react, and a lot of the time, not always reacted the right way. We learn from our own mistakes.
I'm always feeling excited when you see a deer cause your anticipating that the big boy's following her and ready to come into range any second. Problem is when they just appear, right next to ya, when you least expect it, and now it's decision time. Your expected to process all those answers in the blink of an eye. THAT's what's great about the sport, anything at any given moment.