In a recent e-mail article titled “Attitude is a very important word,” Earl Nightingale says that “of all the words in all the languages of the world … ‘attitude’ is the most important.” “More than any other single thing,” he says, “your attitude will determine … what happens to you.” In other words, he claims that attitude determines not only happiness but also success.

To illustrate his point, Nightingale recounts a story about two unhappy young women who worked as customer-service representatives. They didn’t like their co-workers and they liked the customers even less. It got so bad that they decided to quit. But the day before they had decided to resign — just for the fun of it — they made a pact to say and do anything they could to make people happy. And so they did. No matter what kind of rude or nasty or whiney behavior they encountered, they responded with kindness, courtesy, and efficiency. What happened surprised them.

Within the course of a single day, all the people they dealt with — customers and co-workers alike — appeared to have undergone major personality changes. By the end of their eight-hour shift, both ladies decided that they liked their jobs and would continue. Nightingale believes that attitude is everything. “If you’ve found people to be reacting unfavorably to you, or if you’ve gotten the idea the world is picking on you, it might be worth your time to study the front you’ve been presenting.” “The way I look at it,” he says, “each of us has a choice, no matter what the circumstances may be, to either be cheerful or not.

There is absolutely nothing to be gained by being grumpy, so why even consider it? If you develop the right attitude, it’s amazing how quickly the world changes — how things start to go your way — and how lucky you seem to become. Like the two girls in the customer-service office, you might make an amazing and interesting discovery.” Nightingale is right — but not completely. Attitude is very important. It affects the way you feel. If you have a bad attitude, you will usually feel bad. If your attitude improves, so will your mood. Having a bad attitude can limit your choices.

If, for example, you don’t like your partner, you’ll probably think about breaking up with him. Had you a more benevolent feeling about him, you might consider other, more creative options. But attitude is not everything. If you want to change your fortune in life, you don’t have to change your attitude, you have to change your behavior. Success — what you accomplish in life — is determined by how you act. You can have a very lousy attitude and still be eminently successful at your career. (I can give you plenty of examples.)

Contrarily, you can have a terrific attitude about life and be — by conventional standards — a total failure. (I’ve made this point before — and it’s been contested before — but I think it bears repeating.) I believe in having both a good attitude and good behavior. I want a good attitude because it will make me happy. I want to practice good behavior because it is the only way I will accomplish my goals. If I want to become a great novelist — and I admit it, I do — it won’t do me any good to say a thousand times, “I WILL be a good writer.”

What I need to do a thousand times is write. If I spend a thousand hours writing, I will become a competent writer. If I spend five thousand hours, I’ll be a damn good one. (See Message #108, “How Long Will It Take You to Do What You Want?) I hope you don’t think I’m splitting hairs. This is an important distinction for me, because I’ve seen too many people spend too much time trying to improve their attitudes yet do nothing concrete about improving their lives.

In past messages, we have talked a good deal about how to defeat lethargy, overcome depression, and get more energy and optimism into your life. But we’ve spent even more time discussing specific techniques for changing your behavior. We do that because we know from experience that if you want to do more and better than you are doing now, you have to do — and not just think or feel — differently. And that’s good. Because sometimes you just don’t have enough energy to change your attitude. But you can still wake up extra early, chart out a “to-do” list of important tasks that will get you one step closer to your ultimate goals in life, and actually make some progress.

And the bonus is this: The best way to improve your attitude (much better than affirmations, contemplation, or meditation, in my book) is to do something productive. Getting back to the Nightingale story with this perspective in mind, you can see how the story proves my point. What these two ladies did that made the difference was not a matter of changing the way they felt about their customers and colleagues. (In fact, they expected those people to continue to be miserable.)

But what they did change was the way they acted. And when they changed their behavior, everything else changed too — their customers, their colleagues, and their own feelings about work. Just do the right thing. A little bit every day. Before you know it, you’ll have your success.