Did you know that the block of marble from which Michelangelo carved his David had been discarded by other artists? They considered it defective and they were right. Michelangelo saw the defect as a challenge, and created his masterpiece. Eric Weiner adds a great quote of Ernest Rutherford to this piece of information in his book "Geography of Genius": "We have no money so we will have to think".
Source: Eric Weiner, 2016, Geography of Genius, 104