Don't forget the 3-byte encoding they invented and call it 'utf8'.
I remember reading the MySQL Gotchas page back in the 2000s and that leaping out as a particularly egregious issue. It fit in with their whole ethos of "databases don't need transactions and users don't need errors" around that time though, which put me off for life.
I've never been so offended by a technology as the day I discovered that; it's not a misfeature and its not a bug -- only pure malice could have driven such a decision