Experts know that growth requires deep focus. But deep focus narrows perspective. Expert performers rely on the reflection and perspective of experienced observers.
You cannot see the system you are in because you are in it! The fish cannot see the sea.
Every repeat performer relies on reflection and from a critical observer. A coach or mentor who can see wider than the performer. They are key to help turn motion into progress.
Anders Erricsson is the world class researcher on performance expertise. He points out the 'must haves' to become an expert performer. One is feedback from an experienced observer. The observer must know what high performance in your field looks like.
No sustained performance ever happens alone. Learning teams win the long game.