Nobody likes to hear it, and nobody likes to say it - "No!"
No, is the single most divisive word in any language. It makes you feel like a jerk and it makes others want to either cry or punch you in the face.
However, if you look at all of the great men and women in history, you will find that all of them were who they were because they used this hurtful word quite liberally.
No In Business
"And it comes from saying no to 1,000 things to make sure we don't get on the wrong track or try to do too much. We're always thinking about new markets we could enter, but it's only by saying no that you can concentrate on the things that are really important" - Steve Jobs
As a leader in business, you need to be able to set constraints or else you are dead. Saying no to new software, the latest marketing fads, feature requests, customer complaints, new accounting tools, joint ventures, new partnerships, networking events, and so on, are just a fraction of what you are bombarded with on a daily basis.
Constraining and eliminating things that aren't necessary leave you free to focus on what works and what will please your customers.
No to Desires
"Who has courage to say no again and again to desires, to despise the objects of ambition, who is a whole in himself, smoothed and rounded." - Quintus Horatius Flaccus Horace
You don't need to be a hermit, but the ability to say no to yourself is far greater than saying no to others. Your desire for food, money, power, and other things are often nothing but fleeting moments that promise big things, but deliever little.
The power to say no to shiny objects that pass by is the making of a leader and a peaceful soul. Not to mention, the focus you develop by letting go of every want that ops in your head leads you to great productivity and happiness.
No to Ignorance
"I sometimes think of what future historians will say of us. A single sentence will suffice for modern man: he fornicated and read the papers." - Albert Camus
We live in a society that is drenched with information, but ignorant of life. Television, newspapers, movies, radio, Internet, give you an I a feeling of understanding - but nothing could be further from the truth.
Would you give up an hour of television a day to learn the fundamentals of rhetoric (speaking well), or marketing, or how to build a website? If you are like most people, sacrificing an hour of sitting in front of a screen and doing nothing that is edifying is almost unthinkable.
My wife and I gave up television a couple of years ago. Sure, we watch movies from time to time, but no cable, no network television, nothing. How did our friends respond to such a discplined action? Well... let's just say we've been called "crazy" and/or "Amish" quite a few times.
But... since then we've started a successful business, a couple blogs, created a bunch of products to sell, wrote 2 books (one on this site and the other on Kindle), and a whole lot more.
Life is not worth watching television, or reading magazines, or other ways of wasting time. You will be dead soon, start living by saying no.