It isn’t that there are suboptimal patterns, it’s just the more expressive your language can be at runtime, the less you can reason about statically. An example

It isn’t that there are suboptimal patterns, it’s just the more expressive your language can be at runtime, the less you can reason about statically. An example is data-dependent control flow. If you can’t reason about what branch your code is going to take statically (without your runtime data) it is harder to generate fast code for it.