Well, beyond the sheer social resistance to the idea. Turns out everyone needs to agree it’s a great idea and almost no one did. Evidently humans are wired to the base12 time format far better.

The attempt at switching to base10 time quickly fell apart when people started notice that the the “time markers” were starting to drift. And at some point they finally figured out that what we call “noon” was going drift rather quickly to not happening until evening and therefore Monday was going to move to a different spot also. This is a very bad thing. Because any kind of calendaring system needs to be as consistent as possible. Noon must happen at the same point in the day every day or as close to it as it it can mathematically get. If it drifts to fast and far, then it’s a worthless marker for time. And decimal time has that problem in spades.

Now, no calendar system is perfect because the orbits of the planets in our solar system isn’t perfectly consistent. Sometimes the orbit of earth is a tiny bit faster or sometimes it’s a tiny bit slower. So we strive to get a close as we can but we still need to make adjustments. Turns out, all that math is really bloody hard.