I still occasionally stumble on the sequencing of arguments for chmod/chown and I can’t tell you off the top of my head which demands -r or -R. I’ve been doing this for years.
Oof, yeah, I hear you. Also I can never remember useradd vs adduser. That's hardly a scratch on the surface of the issues I have with unix utilities. Which isn't to say that I've seen any operating system with better utilities, but it's not hard to imagine (with the benefit of hindsight) how these might've been better designed.