A life spent making mistakes is not only more honorable, but more useful than a life spent doing nothing. George Bernard Shaw
Pure mathematics is on the whole distinctly more useful than applied... For what is useful above all is technique, and mathematical technique is taught mainly through pure mathematics. G. H. Hardy
A lie is more comfortable than doubt, more useful than love, more lasting than truth. Gabriel García Márquez
Lighthouses are more useful than churches. Benjamin Franklin
Fools are more useful to the wise than wise are to fools. French Proverb
The world could have been great if only people had been more useful. German Proverb