I've reached the point where I constantly screw up with conventional calculators I'm so used to RPN.

Alternatively, (❤️ I LISP)

My first professional job was writing FORTH for fruit machines. I'd played with it a bit before on the Jupiter Ace we had which sadly never really took off despite being more elegant than the ZX81.

RPN breaks my brain, I need to refresh myself.

Who needs PEMDAS when you have RPN :)