Leon Fleisher has a CD out called Two Hands.  For a long time he could only play with his left hand.  Now he has both again.  I love listening to this recording.  You can hear his joy at being able to use his right hand.

And he says being without that hand made him think differently about music. 

I’ve had to think about music in a much more detailed manner than I ever had before so that I could really describe what I’m doing…I think I became a far better musician; I became a far better teacher.

So:  don't take your hands for granted.