I thought my heart was going to literally explode out of my chest.
I know that feeling. I shot a buck last year that was chasing a doe all over my area for about half an hour. finally settled down and gave me a shot. I thought after making the shot that the rush would be under control from now on. I was wrong. this season I made enough blunders to last the rest of my deer hunting lifetime and that rush was even more intense this year. what I can tell you though is not far from shooting the spot not the deer. force yourself to think of the deer as not a deer, but as a target. concentrate on the TARGET.
personally, I think it has a lot to do with having such a majestic and elusive animal coming in so close you can almost reach out and touch it, so close it is like high definition. and the realization that you may actually be presented with a shot at this animal after spending countless hours waiting and watching. you go from nothing, nothing, nothing and then its there.