A writer describes how the ability to say a single word "No!" made him rich.
Reminds me of "Just say no" movement in the 80s. When I realized, being able to say no is an art in itself, a capability, a strength. Which I still am not very good at.
http://www.independent.co.uk/news/business/news/the-one-word-that-will-make-you-rich-a6757111.html