Measure everything and be extremely critical. Be ready to challenge common and popular held assumptions. Here is something I wrote about extreme performance in JavaScript that is discarded by most programmers because most people that program JavaScript professionally cannot really program. https://github.com/prettydiff/wisdom/blob/master/performance...
These are good performance improvements, but they clearly come at a cost. Race cars are faster than sedans, but the tires fall off and they explode without a team of engineers supporting them.
The best people I can hire can mostly use a computer. They can’t build something like this, or even build upon it. They need recipes to reuse to accomplish tasks, and the more something is custom, the harder it is to teach.
And product only cares about performance when a customer mentions it, which is almost never.
I long to spend time tuning race cars, but mostly I assemble sedans.