Damn near took off the tip of my left hand little finger with a conveyor chain once, on the fifth day of a new job. Got lucky, only had a compression laceration that took 5 stitches to close up (and a really gnarly looking scar to show off for the rest of my life). No ass chewing required, especially as when it happened, I went up to the break room and rinsed it out, then put a dressing on it and went back out and worked for another hour, before the boss sent everyone home. THEN I took a trip to the emergency room to get it looked at.
Had a co-worker (my best friend in high school), when I worked as a stock boy at the local grocery store in high school, who spilled ~25 gallons of milk one time. We were told that under no circumstances were we to stack more than 5 crates of milk on a hand truck. Each crate held 6 gallons, and 30 gallons on a hand truck was already a pretty hefty load to handle. He got in a hurry, put a 6th crate on the stack, and headed out the door......only to have some fat lady with a grocery cart in his way. When he tried to stop fast, that stack of milk crates split in the middle, and all 6 crashed to the floor. Out of 36 gallons, about 11 survived. He got a pretty good butt chewing for that, AFTER he mopped it all up!