Example: The Myth of Five Nines...


Aside: Arbitrary Optimization Considered Harmful 

Why? 

Because optimization introduces complexity and tighter coupling between components and layers
Not always: "The best code is no code" [Randy]
Virus evolution argument

The implication here is that trying to squeeze out efficiency past some point only adds complexity, increases system non-linearity, and hence leads to less reliable systems (Law of Diminishing Returns)
But still, why?