Why is it impossible to tune a piano?

That seems like a silly statement, doesn't it? Of course a piano can be tuned! I pay to have a professional tune my piano regularly. It is part of being a responsible piano owner. All that is true... but this video is a great explanation of the challenges that tuning a piano present and why a professional is needed in the first place. Take a few minutes to watch it: Thank you to Minute Physics for this very well done video!