This is a great question, but I could never imagine being able to pick just one.
Despite that, I've worked many years in venture capital / private equity -- there is one thing we must communicate to people constantly. It's an extremely important premise to understand for anyone that believes they have a "million dollar idea."
Genius is 1 percent inspiration and 99 percent perspiration
Simply put -- No matter how much you believe your "million dollar idea" is worth, in most cases it's worth (essentially) nothing .. unless you're willing to dedicate yourself to hard work to achieve something others have not. Hard work is far more important than mere creativity and both are required for success.