One thing that is a bit amazing to me is that there are all sorts of absolutely bonkers rules to English that 99% of people can’t describe, but do subconsciously anyways. Things like the order of adjectives (“big red ball” sounds right, “red big ball” sounds wrong) are surprisingly complicated [1], but we passively learn them at a young age.
[1] https://dictionary.cambridge.org/grammar/british-grammar/adj...