I would add most programmers don't know some time zones have offsets in minutes. In ancient times, some were in seconds.
I live in UTC-04:30 and regularly encounter bugs because of it.
Here in Germany (which once consisted of 100-or-so small states), the introduction of a unified timezone only happened when railroad systems were built, because people noticed for the first time that their clocks were off by a slight amount.
Until the unified timezone happened, timetables would be printed with multiple timezone information. So maybe your train would depart in Dresden at exactly 14:00 Saxonian time, take exactly three hours to drive to Berlin, and arrive there at 17:06 Prussian time.
Until the unified timezone happened, timetables would be printed with multiple timezone information. So maybe your train would depart in Dresden at exactly 14:00 Saxonian time, take exactly three hours to drive to Berlin, and arrive there at 17:06 Prussian time.