We can differ on what we mean by &quot;micro,&quot; but I think our intent is more or less the same. There is such a thing as anticipating performance problems and designing for them, and there is such a thing as losing sight of the performance needs of the code you&#x27;re writing.<p>At the end of the day, it&#x27;s another expression of the 80&#x2F;20 rule: do the 20% of the optimization work that affects 80% of the runtime. But outside of general knowledge of where the inner loops are, you won&#x27;t know what that 20% of code that touches 80% of runtime is until you measure.