What is sad is not to be able ...

What is sad is not to be able to do today what you have done in your youth. But what is good is to remember that - when you were able - you did it to the best of your ability.
 Placido Domingo

Quotes from the same author

If money was my only motivation, I would organize myself differently.
 Placido Domingo
On the other hand, I have devoted so much energy to reach the top that I accept the stress of being there.
 Placido Domingo
I then realized that I could never be satisfied again with the mere natural charm of my voice, that I had to constantly paint when singing, melting all the colors, expressing reds and blacks that had to be less primary but bursting with subtly colored combinations.
 Placido Domingo