I mean it’s a minor difference and you get used to both systems, but like I said, by cutting the scale in half from 24 to 12 you’re magnifying the difference in time. For instance, 3 to 6pm on 12 hour clocks is 25% of the scale whereas it’s actually 12.5% of the overall day on 24hr scale. But you don’t experience the overall day, you sleep for a big chunk of it. In other words, the 12hr clock is more appropriately representing that time to you as a portion of your waking day.
Consider this: if I told you the time in an accurate but larger quantity, how would it look to you? Like if I told you that my clock is 48 hours and resets every two days to go from 0 to 48, wouldn’t it change your perception of time? It creates dissonance that a 3 hour meeting would feel very long and yet it is such a small portion of your two day clock. That’s kind of how Americans feel about 24hr clocks.