I may or may not have done that to a headteacher's printer on a last day of school.
The page count was somewhat higher. In fact it was several times the capacity of all the printers in the school put together.
Bear in mind this is a number of years ago, when school IT was a little less sophisticated (I presume it's better now, anyway).
That reminds me of being at college where they charged you per page (2p?). The only problem is that it was originally not implemented all that well and all the software that charged you did was pause the print job until you clicked on the pop-up window for the charging software (which gave you the option to accept or cancel). The problem was is that we could still access the print queue from the printer icon that popped up in the task bar, and therefore un-pause the print job. When printing had completed you just cancelled the pop-up window and did not get charged!
As for worst workplace cockups I have not had any that dramatic mainly stupid things like, tripping the electric when testing to see if something that has been brought back that a guest claims is broken, not just killing the back area of our overgrown shed but the accommodation managers office and her now essential computer as well.
Also overwriting PAT records when forgetting to use 'save as' on the previous days one that I used as a template (luckily having printed off the previous days first), or once smashing the window on a caravan when the roll cage that I had a pressure washer in decided to roll down a small bank and into a window.