[hyperpallium2]

He's making a more general statement, with "root of all evil", that improving some aspect of something without understanding its effects on the whole outcome, is literally the root cause of evil in the world, in general. Winning the battle but losing the war. Not seeing the forest for the trees. Getting lost in the weeds. Unenlightened self-interest. Not hyperbole, but a particular instance of a general concept.

But on code optimization, k deeply nested loops are not a bad guide to O(n^k), and a candidate for optimization.

That said, I once cached something that obviously needed to be cached - so obvious in fact that a deeper level in the system already cached it.