Automated testing software. You know, the type used by HR agencies to screen candidates and see whether they can do complicated things like entering data in Access or creating a formula in Excel.
The problem is that any decent software interface provides multiple ways of performing common tasks, so that people can find their own way of working. There's at least three different ways of changing the number format in Excel, for example... unfortunately, the piece of software I was playing with today recognised only one of them. Mimicing the complete user interface was too much work for the programmer, it seems - so as a result, people who don't do things exactly the way some braindead HR prole does them end up swearing repeatedly at the screen.
Then there's being asked to create a macro to do X, then being told you can't use the VB editor to write it. Grrr.
The best way to test software proficiency is to give people a suitably complex task, and then examine the results. Unfortunately, this would require that the tester actually knew something - and of course, if they knew anything, they wouldn't be working in HR.