A knee that worked the way it was suppose to.
How much would I change before I was not me any more? Our physical shell shapes our spirit more then we care to understand. Being shorter or taller changes your perspective and so changes you at a fundamental level. Being blond or a redhead changes other peoples perspective and so changes the way you relate to them.
I am happy as me. Do I really want to risk changing that?
On the other hand if you could build in a flame thrower into my arm so I could get through my paperwork really fast I might risk it.
Exactly. My central character doesn't want to accept change.
This story has been written before. It was called "Peter Pan".
He didn't want to grow up. But what if you could pick an age, (or return to it)? Which age would be best?
That too has been asked and answered numerous times. But we all still come up with different answers.
One truth is that we fit the age we live in best at different ages in our lives. We are more accepting as children, more understanding as adults, and more tolerant as older folks.
As a child, I wanted to embrace the world, and I did.
As an adult, I wanted to understand the world, and I thought I did.
As an older fellow, I'm ready to go back to wanting to embrace the world.