There are different kind of hardship though.

There things which was a result will make your mind click to an other way to comprehend a problem space and how to navigate through it.

And there are things which are hard due to pure accumulation of concurrent conventions, because of reasons like coordinating the whole humanity toward harmony with full happy peaceful agreement of everyone is tricky.

Handling date is rather the latter. If you dig in the lucky direction, you might also fall into cosmological consideration which is a rabbit hole of its own, but basically that's it: calendars are a mess.