Perhaps you've spent the last ten years scripting. I, however, have spent it writing applications. And boy do application users whinge when things run too slowly.

Yes they do.

They also whinge when the functionality they need isn't in place because the developers are having to deal with this god awful tightly coupled unmaintainable mess that's been produced in the name of efficiency.

In my years of writing applications I have had far more problems due to programmers trying to be clever in the name of efficiency than I have with programmers not being efficient enough.