My first shot while deer hunting was a 40yrd shot on a doe when I was 17. Double lung and heart, passed through. She ran about 30yrds and collapsed. I had been rifle hunting deer for a few years before that, and I had been shooting competition archery for a year. I also grew up hunting rabbits with a fiberglass recurve as a kid, so archery was something I was used to.
That said, missing is part of archery, and especially a part of bowhunting. Having a laser rangefinder (or pre-measuring different landmarks around your stand) and practicing at LOTS of different ranges helps a lot.
One of my "favorite" miss stories, whether I like to admit to it or not...
About 6yrs ago, I had a SIMPLE 20yrd broadside shot on a doe from a ground blind... I leveled my bow and took the shot, but for some reason, it fell low, REAL low. Amazingly, she didn't move, just looked THE OTHER WAY, towards where the arrow hit the ground past her. So I checked my sight, and took another shot, again, same deal, dropped it in the dirt beneath her. She hopped a little and trotted a few steps and luckily stopped. So I checked my sight again, and took a 3rd shot, holding a little higher, thinking maybe I had underestimated the range. Stuck a 3 blade thunderhead right in her spine, about 10" above where I was aiming.
Then when I walked out to recover her (and my 2 missed arrows), I figured out what was going on. There were two small, thinner than a pencil, branches hanging from a tree limb between my blind and where she had been standing, about 5yrds in front of her. I just couldn't see them in the morning fog, so I bounced my first two shots off the branches. Unfortunately, I thought my sight was messed up, so I compensated for the drop on my 3rd shot. When she trotted away from the tree, AND I compensated for the drop, I ended up shooting WAY high. Luckily, the two first shots missed completely, and the 3rd shot dropped her in her tracks.
Like I said, misses happen.