I wonder if this could be summarized as something like: Efficiency is only useful until it imposes on some degree of slack, or spare resource, which allows you

I wonder if this could be summarized as something like: Efficiency is only useful until it imposes on some degree of slack, or spare resource, which allows you to respond to aberrations which (inherently fragile) efficient systems can't accommodate very well (Although you could argue that an efficient system would accommodate systemic aberrations well, but then I wonder if it would be a semantic argument). Sort of like with finances. You could optimize your spending and investing as though economics are totally determinate, but they aren't, so you keep some cash as slack to accommodate cases where the shit hits the fan. When working on a project, you could schedule your time down to the wire and work as hard/smart as possible to hit the deadline perfectly, but it's not going to work out well every time (or often at all in software). So you figure alright, it seems like something that should take 3 days, I'll bank on 5. If you come in over or under, it works out well for everyone. There is not point in trying to max out on efficiency in these cases. In determinate environments where things really do work exactly as you'd expect, well, it's a different story. But human beings aren't that.