Consistency.

Marco Pierre White prepares salmon piperade ...

Life in the kitchen is about consistency, it's about focus, it's about discipline, and punctuality.  If you're late, you'll always be late.  If you can't focus you'll be inconsistent.  If you can't stay disciplined, you'll deliver inconsistency, again.  

The key to survival in those three-star restaurants is punctuality, discipline, focus, which all equal consistency and that's what three stars is all about -- consistency.