I saw some of these during a machining class near Boeing. Most were actually trying to learn but it felt like high school with them fucking around on the machines. Some were real serious which is who I talked to.

The worst were the folks who were literally of the opinion that they just sat through this bullshit like a mushroom and they'd check the boxes to move up one grade at the union. One of these was a dude who constantly complained out loud about the math. Machining feeds and speeds is based on the surface feet / minute or your metric equivalent of the speed of the outer diameter of your cutter. So pi is used a lot. The equation is on every wall. 5 minutes in while everyone was signing paperwork I had reversed the formular for every variable. Page 3 of the book does that for you and makes pi 3 for ease and safety. This was the math the guy complained about. We had to do it 5 times total. 7 classes in this dude still had not brought in a calculator and the laziest kid in the class mocked him for it. This same guy who couldn't / wouldn't do the math spent an hour at lunch explaining his intricate scheme to basically work 14 days each year for the next 2 years before exiting out to part time and then retirement with his full benes. So he could do it, but he just wanted to sit at home playing guitar and drinking and subjected the rest of is this complaints. Also he hogged the professors time a lot.

There were some others who did not have the math skills to do offsets/ zero setting on depth of drill holes. But when the professors could give them the time they could usually come up with a way to explain it. That guy wanted to learn but also felt that once he was certified his job was to read a book until the machine went into fault mode, so the training got him an easier job. He didn't actually need to understand any of the training to hit a button when a light went red.

Hopefully the instructor in those cases is willing and able to just flunk the students who aren't trying, or just aren't capable of handling the material.