Here come some personal ones:
+ One time in my university (Business School)(I am also a software student), someone flip down the screen (Ctrl+ up arrow) of the class PC that the profesor needs in other to show his PTT. And we waste 3 hours of class trying to fix it (I was the only one who knew what was happening), and then the class was suspended (The I.T guy was sick that day so GG EZ accounting class...)
+ In my first job, I worked at a company with average cow workers age of 50 years. The things that I saw there.... oh boy... for saving a word document into pdf they print the paper and later proceed to scan the document (what a waste of paper). To storage things, they buy USB flash drive (they use them like they were folders), so they have like 1550 usb in one looker... and in other to search thins you would need a paper index, with the "number code" of the flash drive. Some USB has only one word document (was a 2G flash drive). So one day i back up all the data in a external hard drive (it was less than 5G of data), and that was how i get that day free "because my good work". The next day, the continue using fucking flash drives... I try showing google drive or Dropbox... but man.... I think they love to waste money buying flash drives.
+ And for the last one: Me and my friend went to a company to do a work for the university, were the I.T. department at 1 pm (they start working on 9 am and have to work until 5 o 6 pm) or even earlier, every time, they said to the boss "We need to wait, the program is compiling " and them proceed do nothing... just wait in their desk or go out to do something more. (Obviously they know that a small program, or a query in a DB don´t freeze your PC) they only took advantage of their boss... hahaha Five days to do a simple register hahaha because "the program is compiling ".