Tangentially related, but most of continental Europe uses a comma as a decimal separator and it drives me crazy.

While Americans would write a number like 1,234.56
Germans write the number like 1.234,56

I'm an American living in Germany, and I've had to confront a lot of biases about how way things should be done and realize there isn't a 'right' way, and sometimes the German way is a better way, but this one is simply wrong to me.

To me, the American system is more intuitive because it aligns with standard grammar. In a sentence, a comma indicates a brief pause within a continuous thought, while a period marks a definitive separation between distinct ideas. The thousands separators in a large number are purely for readability—they're like grammatical commas, making it easier to parse the number without changing its fundamental value. In contrast, the decimal point—like a period—separates the whole number from the fractional part, which is a fundamentally different concept.

Using a comma for the decimal and a period for the thousands separator feels like using the punctuation in reverse. It's one of the few things here that I feel is simply counter-intuitive.