I literally found the instruction manual for the pile of phones at a store I worked at and figured out how to make it do things that were useful.

One of which, was changing the fucking time after Day-Savings-Time because the phones were fancy enough to have it hard coded into them, but not fancy enough to be updated after the date of Daylight Savings changed. So for YEARS the phones would spend like four months with the wrong time until the time changed happened again.