Basically, when you're using a calculator, you're calculating, not notating. With RPN, you have a data stack, and everything you do is an action you perform on

Basically, when you're using a calculator, you're calculating, not notating. With RPN, you have a data stack, and everything you do is an action you perform on this stack (like entering a number or doing an operator). You can see your calculation in progress. It can be somewhat natural to put verbs at the end ("3 and 4's sum" for instance), and you don't have to think ahead to figure out whether you'll need parentheses. If the expression gets to complicated, though, traditional notation is nice because it's easier to verify you calculated what you intended to, I feel. But let me deconstruct your gripe. A good part of mathematics has been about finding the right notation to express particular ideas. RPN, in my experience, makes it easier to express certain calculations to a machine. But: why is there 'should' and 'have to' in your gripe? No one is forcing anyone to use RPN. You struggle with it to learn the notation, and maybe it makes the "difficult mathematics" easier to deal with. It's not like people make RPN calculators to be intentionally difficult and alien. Your gripe could equally apply to modern algebraic notation vs. the old latin longhand, or arabic numerals vs. roman. I'm sure it was a struggle for people to learn the new notation in either case.