Every time I yell, my wife comes out behind the house, with a big grin on her face. Then, she asks, "What happened?"
I have a theory about this. I think that there is a part of the brain that works when a person is flintknapping, which we are not always conscious of.
To give an analogy, when a person eats food he actually creates, controls, and applies, pressure. He does it over and over, via mastication. If a person has a small lemon drop, or piece of hard candy in his mouth, he will unconsciously turn it, and crack off chips, via pressure. We do not really think about it unless we inadvertently do something like bite down on a metal fork. Otherwise, while not making a mistake, the brain seems to work almost unconsciously.
In flintknapping, I have always felt that some part of my brain was guiding me, apart from language, and conscious thought. And, frequently, if I overthink what I am doing, my hands fumble. Sometimes, I try to make myself stop thinking, so as to not ruin the flintknapping process. But, in order for this to work, a person has to practice ALOT, until the processes become second nature.