Originally a comment by Nullius in Verba on Nobody asked for this tragedy.

I’ve introduced several people to basic trap shooting. One thing that often happens is they’ll shoot once and then find that the shotgun won’t fire the second shot, no matter how hard they squeeze the trigger. Some of them even try to turn to me, and I have to physically hold the muzzle downrange. There’s nothing wrong with the gun or the ammunition—they simply were so overwhelmed by the pressure that they couldn’t release the trigger enough to allow it to reset for the second squeeze. This has even happened when it’s just me and one other person in a field out in the middle of nowhere. That’s how little pressure it takes to fluster an adult to the point of being unable to perform simple motor operations and almost pointed a loaded shotgun at a person three feet away with a finger squeezing the trigger. It’s not a scored competition, not a pheasant hunt, and certainly not a life-or-death defensive situation in which any action or inaction can be suddenly lethal. Nothing is hidden, nothing unknown, no need to worry about whether someone has a weapon that could kill you or someone else before you have time to fumble with your safety.

I’ve personally seen grown men wrestling and one not realize that he cut off the other’s breathing until a third party broke them up—because he saw the second man’s shorts go dark with urine.

One of the most common causes of car crashes is that drivers get flustered and put their feet on the wrong pedal. They try to stop, but instead of slamming the brakes, they floor the throttle. And they don’t even realize they’re doing it. The trap shooters are the same way. They aren’t even aware of what they’re doing. The stress of the moment shuts off the executive function required.

Stress impairs performance, awareness, and decision making much more easily, quickly, and severely than most people realize. Sure, we have the phrase “armchair quarterback”, but few really understand the depth of the advantage afforded by the armchair or why athletes (and police, and soldiers, and surgeons, and debaters, and on and on) train so much, repeat the same prescribed series of actions so often. You do on the field what you train in the gym. If your range training requires that you immediately raise your hand and set down your weapon whenever you have a misfire or some other mechanical failure, then that’s exactly what you’re going to do in an actual firefight—and you’re going to get shot. Everyone has a plan until they get punched in the face, which is why boxers have their coaches in their corners constantly reminding them of the plan.