When my father-in-law was a college student he was using a table saw to cut aluminum stock to make a 2" cube. He had the fence on. As he finished the cut, the 2" cube turned between the blade and the fence and launched at him, hitting him right on the lens of his safety glasses. He never saw the cube--it went out a window after bouncing off his glasses. His safety glasses were crushed, and he had pretty deep cuts and bruises around his eye.

He tells that story when he thinks people aren't having enough respect for power tools. He could have been much more severely injured. If he hadn't been wearing safety glasses he definitely would have lost his eye and could have had brain damage as well.

Human strength and reaction times are so insignificant compared to these machines. It's purely an illusion that we are in control of them, and there's no reason not to use all of the safety measures and precautions available to us.