A great quote from Lord Acton, explained by Paul Graham:
"Lord Acton said we should judge talent at its best and character at its worst. For example, if you write one great book and ten bad ones, you still count as a great writer-- or at least, a better writer than someone who wrote eleven that were merely good. Whereas if you're a quiet, law-abiding citizen most of the time but occasionally cut someone up and bury them in your backyard, you're a bad guy."
I couldn't agree more. I'd rather attempt big things and fail most of the the time. If you attempt small things and always succeed, you'll also succeed at eliminating the possibility of greatness.