> In my view you should make it a habit to write optimized code.

It depends on your domain.

If you're writing for embedded, or games, or other things where performance is table stakes, then sure.

If you're writing code to meet (always changing) business requirements in a team with other people, writing optimized code first is actively harmful. It inhibits understandability and maintainability, which are the most important virtues of this type of programming. And this is true even if performance is important: optimizations, i.e. any implementation other than the most obvious and idiomatic, must always be justified with profiling.