I could not do the same thing over and over again for 8 hours. My arms would be ready to fall off and my brain ready to explode from lack of thinking.
Probably would be a lot better if these workers knew every different line job offered and could switch to a different job every day or at least a different one every week. But I am betting the lug nut guy does lug nuts everyday he shows up to work and that would be mind numbing, literally.