“One of the biggest mistakes engineers make is spending time on optimising something (a component) that shouldn’t exist in the first place” - Elon

I’ve been guilty of this a few times 😅

I been made to do this by a client.

Optimize their 20yo, mission critical Excel-sheet-turned-SQL-DB instead of taking both it and its creator (who was still holding a fairly influential position in the company) out into the woods.

I quit. So did my junior. And the two trainees who were supposed to replace us.

That is where engineering becomes research:
You start optimizing something and then slowly realize, that the architecture is flawed. Then you start refactoring to ease fixing the architectural flaw and on the way obsolete some components...