We went metric/decimal here in UK about the end of the 60s & beginning of 70s ~~ decimal currency replaced our old £sd in 1971. The Head of Maths in the school where I was teaching at that time accordingly put in an order for 100 metric rulers ~~ to receive a reply from the suppliers that they were available only in one-dozen lots.
Any other such illogicalities to report in your experience; especially, like this one, in the face of change or progress?