From Ollie White's MRP introduction:
"The reason people think computers will make everything faster [and better] is that the first thing ever computerized was the company payroll. Payrolls were already well understood and manual systems had evolved that described [their workflow] perfectly."
He then goes on to illustrate why that is never true for anything else, especially in the manufacturing world.
It would seem that the new payroll system would never have worked manually either. Spotting that before anyone puts mouse to desk is the trick (and the greater part of Ollie's talk that day).