I had to watch a bunch of these as part of mandatory safety training before I could use the student machine shop. I had to leave the room because I was getting light-headed, the one with the guy being slowly dragged through some kind of roller-press was too much, also maybe I didn't eat enough breakfast.
I used to work installing and refinishing hardwood floors in my early early twenties. On my first job alone the boss tells me when dropping off equipment in the morning to put on a few coats of lacquer by days end and gives me a respirator, offering no instructions.
At some point I got a headache, then on the bus ride home I started feeling ill like nothing else. I had to get off the bus. I get out the door and start barfing. I barfed uncontrollably, writhing on the sidewalk for about 8 minutes. I finally got myself together, dizzy, and nauseated and made my way back home. I was sick for two days after that.
The filter cartridges had filled up and I hadn't noticed; nor did I know I should have been changing them at intervals to avoid poisoning.
I had a similar issue on a summer job in college where we were given respirators to spray on lacquer to siding. Even though we were outdoors, the spray worked out coating the respirators so the filters were completely clogged in chemical. I was out sick for the remainder of the week.
On the same job I also had a 40 foot wooden ladder fall on me after it had been extended to the roof. I came out OK, no one else got hurt but the boss kept me away from ladders for the remainder of the summer.