I only knew(and liked) C reasonably well before Rust. And nothing felt obscure when I started learning it.
I can only remember not getting what `||` meant (in the context of defining a closure without args). The positional meaning of `||` and `&&` is the only thing, I can recall right now, that can be considered obscure syntactically (for C developers at least) . They should have gone with literal `and`/`or` for the operators IMHO.