Only mediocrity can be trusted to be always at its best.
Mediocrity at best breeds more mediocrity, but a master can better themselves.
And don't confuse expertise for mastery. An expert may spend a lifetime honing a skill to deliver mediocrity of a consistent quality. A master will intuitively understand new problems with no time spent. Expertise is dependent on knowledge and experience, mastery is not. One may master without being an expert, but master do tend to be experts.
"Tell me what a class invariant is."
I don't know most terms myself. I typically self discover nearly everything that I know by thinking about a problem for a little bit. I didn't know the term "race condition" when I was 8 years old when I theorized they would be an issue within a few minutes of learning that multi-core CPUs exist. I've been using "tiling" for years to optimize memory access without knowing what it was called. These things just seem blindly obvious when you see the problem.
For performance you don't predict. Experiments are the only thing you have that work
In my experience, I am better at predicting performance than synthetic tests. In many cases, intuition out-ranks empirical evidence because some things are impossible to directly measure, only theory works.
1 1 was a race-horse, 2 2 was 1 2. When 1 1 1 1 race, 2 2 1 1 2.