Just because something doesn't do what you planned it to do doesn't mean it's useless.
“We have to learn again that science without contact with experiments is an enterprise which is likely to go completely astray into imaginary conjecture.”
“A man who dreads trials and difficulties cannot become a revolutionary. If he is to become a revolutionary with an indomitable fighting spirit, he must be tempered in the arduous struggle from his youth. As the saying goes, early training means more than late earning.”