My ability to conquer challenges is limitless. my ability to succeed is infinite.

Nobody has an accurate reading of their own ceiling, because ceilings only get tested by circumstances nobody arranges on purpose. The fortnight when two people were off and the work still went out. The day you handled something you would have said, the previous Friday, that you could not.

Those weeks are horrible while they happen, and they revise the estimate permanently. Afterwards the old figure is unavailable. You know something about yourself that cannot be un-known.

That is the mechanism, and it has no obvious stopping point. Every hard stretch you get through moves the number, and the number was never fixed to begin with.