I previously did residential heating oil. I was the top guy at the company, so when someone applied, I would evaluate whether to hire them.
Guy came in and was all full of himself about how great he was and how awful his previous employers and coworkers were. He drove past stops a few times and made idiotic turn arounds to get back to them. He supposedly had been driving oil trucks for years, but had questions every step of the way about loading.
I told the boss that he seems woefully inexperienced (they weren't looking to train someone), but I didn't think he could even be trained if they wanted to based on his attitude.

I saw him at the rack ~3 weeks later loading for a different company. He was top loading (like most of us do), but wasn't paying any attention. I don't know how he managed it, but he filled the roof, and had oil pouring off the sides of the tank before someone in another top loading rack pulled the emergency shut off to turn off the entire facility...before he even closed the valve. He also left the roof vents open, so all of that oil was also just drained right on down to the catch basins.
The facility was shut down for hours until they had it all contained, then it was open only for the bottom loading lanes for another couple days until they finished cleaning it up.

He was obviously banned from the site, and I never saw him again with any oil company.

More tame things that drivers do?
Their last load was gasoline, but after that load, they go to a facility that doesn't recover vapors, so they get temporarily banned and forced to go to training about what is permitted at that site (last load had to be diesel/ho/bio).
Scullying out is a 1 day ban first time, 3 day ban second, 7 day ban third, and 7 day or permanent for any time after third.
A big one is not reporting problems. Did you get a dyed diesel load that didn't inject dye? Report it. Loading head is doing more than a tiny drip drip? Report it. Damaged equipment (loading heads, scully, etc)? Report it. Yes, even if you caused it.