Many years ago i worked as a computer operator and in the computer room there was a digital clock with numbers that flipped over when the time changed. We started work at 06:00 am and when we arrived the time had changed but the clock showed an hour slow so one of the operators stood on a chair and put the clock right by changing it a minute at a time which took him about 15 minutes to do as you had to do it one minute at a time. At 07:00 am the maintenance staff for the company arrived and changed the master clock in the basement to put all the clocks in the building to the right time. It changed our clock so this was now 23hours out!!!!! The operator ( who was a geordie) had to get back on his chair and put the clock right a minute at a time for the 22 hours it was out as it would only change forward not backwards. Result a geordie with a very sore finger and back who never changed the clock again and a lot of very amused workmates.