I think in an earlier post I detailed how I always wanted to learn RPN/RPL, and was working my way back through college algebra/geometry/trigonometry on an HP 48g and 50g.

I've spent so much time lately in RPN that I needed to do some simple math, and the only calculator I had available was Windows CALC.EXE.

I was absolutely stymied by calc.exe's apparant inability to add five numbers together and divide by five.

"Why is it telling me the average is 5?"

"I wish I could see the stack, how can I be screwing this up?"

After about thirty seconds I realized my error, and then it was actually painful to make myself think in... infix notation, I think it's called?

"Enter the number, plus, second number, plus, keep going, now 5, divide, crap, that should have been divide, THEN five, but wait it only divided the last value by five" etc. etc. etc.