We are all apt to get carried away with the apparent uniqueness of our talents and thinking. I'm often reminded of the story of Picaso visiting the cave art at Altamira. When he emerged shaking his head he was asked his opinion. Picasso replied:
“In 15,000 years we have invented nothing...”

Otherwise there's another favourite quote: Sterne's Admonishment on how ideas can run away with you:

"It is the nature of an hypothesis, when once a man has conceived it, that it assimulates every thing to itself as proper nourishment and, from the first moment of your begetting it, it generally grows the stronger by every thing you see, hear, read, or understand...”

Lawrence Sterne: Tristram Shandy.