It's too slow. Now what? You have to use asymptotic analysis to figure out that it's O(n^3) but can actually be performed in O(n) - then write the derived code

It's too slow. Now what? You have to use asymptotic analysis to figure out that it's O(n^3) but can actually be performed in O(n) - then write the derived code from your analysis. Nothing has changed. Customers care; transitively.