[mantas]

For example having local time vs official time. This is what remote cities in western China are using. They've to use same time as east coast, but it makes no sense at all for them. So they plan everything around unofficial local time.

[BurningFrog]

That's an option, but I was thinking we would probably agree to call the days we've always called Thursday "Thursday" locally.

[mantas]

How do you know which was originally Thursday the earlier or later part? Or do you have to calculate it based off old UTC offset? What if you move across the globe? What if you talk to somebody online and they say they're doing smth on Thursday? How do you know which Thursday is theirs?