Talent, potential, and expectations are all nice, but without mental flexibility to control your skills and fulfill your potential, something is always missing.
Sure, you may flash and taste success for limited moments, but sustained success and stability are nearly impossible without the flexibility to be stable.
How is flexibility actually stable, you might ask? Think of it like the ocean, the top can appear calm, while underneath the water is being pierced by animals and forces of all kinds. Yet, the outside that we can see and interact with is mostly calm. The flexible underside allows for the stable top side.
If the ocean was rigid like a stone, it would be initially strong, but if anything pierced it, it would crack and never be the same.
Flexibility will equate to stability and indeed, still waters run deep.