More than 20 years ago we had an intern who was tasked with putting CPUs and RAM on motherboards, which were sold as 'tuning kits' for older PCs. He was left on his own for nearly the whole day, because the guy who was in charge was out for the rest of the day. The next day the when he was back the intern came in and was kicked out immediately, because on all of the ~100-200 kits he built that day the CPU was inserted the wrong way around.