There's a lot of talk, and a lot to be said, for the power of Yes. Yes supports , courage, and an open-hearted approach to life whose grace cannot be minimized. But No—a metal grate that slams shut the window between one's self and the influence of others—is rarely celebrated. It's a hidden power because it is both easily misunderstood and difficult to engage.

It's likely that we are unaware of the surge of strength we draw from No because, in part, it is easily confused with negativity. Either can involve a turning away, a shake of the head, or a firm refusal. But they are distinctly different psychological states.

Negativity is a chronic attitude, a pair of emotional glasses through which some people get a cloudy view of the world. Negativity expresses itself in a whining , a petulant discontent, or risk-averse naysaying. It's an energy sapper. Negative people may douse the enthusiasm of others, but rarely inspire them to action. Negativity certainly ensures that you will not be pleased. You will also not be powerful.

Where negativity is an ongoing attitude, No is a moment of clear choice. It announces, however indirectly, something affirmative about you. "I will not sign"—because that is not my truth. "I will not join your committee, help with your kids, review your project"—because I am committed to some important project of my own. "Count me out"—because I'm not comfortable, not in agreement, not on the bandwagon. "No, thank you"—because you might feel hurt if I turn down your invitation, but my needs take priority.

The No that is an affirmation of self implicitly acknowledges personal responsibility. It says that while each of us interacts with others, and loves, respects, and values those relationships, we do not and cannot allow ourselves always to be influenced by them. The strength we draw from saying No is that it underscores this hard truth of maturity: The buck stops here.

is both the tool and the barrier by which we establish and maintain the distinct perimeter of the self. No says, "This is who I am; this is what I value; this is what I will and will not do; this is how I will choose to act." We love others, give to others, cooperate with others, and please others, but we are, always and at the core, distinct and separate selves. We need No to carve and support that space.

No recognizes that we are the agents of our own limits. For most of us, this self-in-charge-and-wholly-responsible is a powerful, , and very adult awareness. We approach it two steps forward and one giant retreat—giving in to the beloved, to the , to our own urges for another drink or an unnecessary purchase. The closer we get to manning the barricade of self-set limits, the stronger we are. That strength requires the power of No.

No has two faces: the one we turn toward ourselves and the one that creates boundaries between ourselves and others. The struggle to strengthen our internal No, the one we address to our own self-destructive impulses, is the struggle with which we are most familiar. That No controls our vent of rage on the road and our urge for the cigarette. We call that No "self-discipline."

The No we direct toward ourselves comes from an internal self-governor whose job is to contain our urges and manage our priorities within an iron fist of reason. All our lives we may work on refining that self-governor, tweaking it, building it, shoring it up. The huge rewards of our governor's developing ability to say No—not too rigidly, but often enough and wisely, too—are and peace of mind. The power of No is in that payoff.

The No we are able to say to others also evolves through life, beginning with the primitive Nos of our . Anyone who has ever tried to put a 2-year-old into a car seat has real-life evidence. As the 2-year-old begins to differentiate himself—his will, his wishes—from those of Mom, he hurls one loud, endless cry: NOOOOOOOO. No, I won't put on those socks, won't eat that mush, won't leave the park! That primordial, powerful No is the original assertion of the self against the other. For the rest of our days we are challenged to find the proper, effective way to draw that line.

Line in the Sand

How much No is too much? Who turns down a needy friend to tend one's own garden? Where is the line between self actualized and selfish? Who refuses to lend support to the modest effort of a group of friends? What is the boundary between important principles and stubborn oppositionalism?

As a general guideline, five situations benefit from increasing strength to say No.

When it keeps you true to your principles and values. It's a beautiful thing—emotionally, spiritually, and even professionally—to be generous, to be supportive. But, as sociologists Roger Mayer, James Davis, and F. David Schoorman point out in their classic studies of organizations, integrity is as essential as benevolence in establishing interpersonal trust. It is a requirement for effectiveness.

Jack, for example, has always cherished his role as the go-to guy for his buddies. "Jack has your back" has been his proud mantra since high school. So when a close, married friend began an affair, Jack maintained a discreet silence. However, when that close friend asked Jack for the loan of his vacation home as a convenient site for the clandestine relationship, Jack wrestled with his . He wanted to continue to be seen as a great guy, but he found himself uncomfortable being part of a , however secondhand. In the end, he said just that, as he turned his friend down.

Jack's No dinged the a bit and violated an unspoken male code, at least among Jack's peers. Still, if being liked by others is often a by-product of saying Yes, liking yourself sometimes comes only from saying No.

It's remarkable how much some people will ask of you, even demand from you, things for which you yourself wouldn't dream of asking. Protect yourself best from the many who feel entitled to ask by being strong enough to say a firm, clear, calm No.

Take a classic school and office scenario: A happy, popular, slacker colleague asks again to borrow his worker bee teammate's careful notes. Mr. Worker Bee resents being used, but can't think of a good reason to refuse. So he acquiesces. Gets asked again. Resents more. Can't think of a good reason to say No, so he gives in. And so the cycle goes.

Finally, paying to his own feeling of being taken advantage of—instead of focusing on finding a reason acceptable to the cheerful exploiter—Worker Bee turns Mr. Popular down. Scraping up his backbone, Mr. Worker Bee simply says, "No, I'm not comfortable with that."

His No earns him a chilly reception in the company cafeteria for a week or two. It isn't a pleasant time, but it passes. In its wake, Mr. Worker Bee will find a new safety. No is a necessary life shield against the charming users who sniff out softies. It turns out nice guys can say No.

When it keeps you focused on your own goals. When her boss criticized her for the second time as a "Chatty Cathy" whose work was late because she wasted too much time talking, Amy felt hurt and unfairly evaluated. Was it her fault that people loved to stop by her cubicle? How was she supposed to turn away Marsha, whose aging mother presented so many problems, or Jim, who wanted her thoughts on the best way to proceed with their clients? Her colleagues needed her support; them short would hurt their feelings and her relationships.

Amy clearly needs the power of No. Why? Because, loving and being interested in them as she is, Amy is losing sight of her own responsibilities, her own agenda. No is a necessary tool to keep your goals in mind. Frankly, meeting your own goals is what you are being paid for and what will pay off. We all need No to do our job instead of someone else's.

When it protects you from abuse by others. Sadly, our most important relationships often invite our ugliest communications. In part that's because the people closest to us arouse our strongest emotions, and in part it's because they are the people we losing the most. Fear can sap the strength we need to say No, just when we need that power most.

A mean adult daughter is a case in point. Isabelle would insist that she loves her mother, but she also finds her irritating, offering the grandchildren too many snacks, giving Isabelle useless, -driven advice about health, bad weather, or spending. When Isabelle gets irritated, she snaps. She's rude ("Shut up!"), insulting ("Trying to make my kids fat like you, Mom?"), or just downright mean (derisive and contemptuous dismissal). Her frequent assaults hurt Mom deeply, and Mom complains bitterly and often to other family members about Isabelle's treatment.

Despite the support of her family, Mom never draws a line with Isabelle herself. She has yet to pull herself up and say, "Do not speak to me like that." She feels unable to because, quite simply, "This is my daughter. If I tell her she's not allowed to speak a certain way, she is quite capable of not speaking to me at all. I just can't risk it." Stripped of the power of No, we leave ourselves vulnerable to verbal assault.

The invitations are in the mail, but the impending is a mistake. The job looks good to the rest of the world, but it's making you sick in the morning. Your family has sacrificed to pay the tuition, but law school feels like a poor fit. When you find yourself going down the wrong road, No is the power necessary to turn yourself around.

The obstacles to this potent No are twofold: First, of course, you have to be able to tolerate acknowledging, if only to yourself, that you made a mistake. So many of us would rather be right than happy. We will continue blindly down the wrong path because we simply can't bring ourselves to read the road signs. Most of the time, though, we know when we need to draw the line.

The problem is getting ourselves to do it. Accessing your own power requires overcoming one huge obstacle: the cost of dishing out No.

Dishing It Out

Simply, No is not a warm send. It's tough to deliver, in large part because we have a gut sense of how it will be received—not well.

supports our hunch that No is going to register far more harshly than we may have intended. The human brain is hardwired to respond to No more quickly, more intensely, and more persistently than to a positive signal. No is stronger than Yes.

The brain's so-called negativity , first described by psychologist Roy F. Baumeister, Ph.D., of Florida State University, explains why negative experiences have a more enduring impact on emotion than positive events of equal intensity. The brain reacts pleasantly to positive stimuli but wildly painfully to negative stimuli. No matter how you gift wrap it, No is a negative event. This holds true whether we are discussing financial matters (we are far more upset by losing a chunk of money than we are pleased by gaining an equal amount), interpersonal events (negative first impressions are difficult to overcome), or personal information (negative job feedback has a much more profound effect than positive information).

John Cacioppo, Ph.D., and colleagues at the University of Chicago actually measured the electrical output of the cerebral cortex to demonstrate that, across a variety of situations, negative information leads to a swift and outsize surge in activity. One hurt lingers longer than one compliment. Nevertheless, the ability to rapidly detect bad news and weight it so heavily, Cacioppo says, evolved for a very positive reason—to keep us out of harm's way.

And No hurts.

Whether reasonably required ("I can't lend my car because I'm not insured for other drivers"), tactfully couched ("Yours is the best banana bread ever, but my doctor has me on a special ") or firmly asserted ("Thank you for asking, but I am already committed this weekend"), the receiver hears No. And feels bad.

Perhaps we intuitively grasp this brain bias, this neurological oversensitivity to No and for this reason alone are very reluctant to trigger that powerful reaction in others. Too, whether we sense the brain's negativity bias, many of us hesitate to deliver a No because of the real interpersonal damage it may do. No is not generally a way to win friends.

While we are not all equally vulnerable, some of us find the sting of displeasing others absolutely intolerable. We popularly refer to these people as "pleasers," and you probably know the degree to which you are one.

Pleasers are so relationship-oriented that they will automatically say what someone else wants to hear, agree with someone else's ideas, or bow to another's agenda without hesitation. A pleaser is frequently socially perceived as "nice," is usually well liked, and often feels taken advantage of, underappreciated, and uncertain in her . It's not an even trade-off; when you cannot say No to others, you disappear.

There's a third cost to No that causes many of us to pull back: No can lead to conflict. That's a path few of us wish to take if it can be avoided.

You may hesitate to say No because the challenge you anticipate from others has merit. The line between selfish and necessary self-interest is not always clear. You want to turn down an invitation because you don't like parties. Your friend really wants your support. She will vigorously object, and you envision her making some good points. That makes No tough.

But face it: Some people will fight your No regardless of the issue. Such folks take others' boundaries as a personal affront. They challenge you, press you to justify yourself. It is a character style, and a successful one in many circumstances. ("Don't take No for an answer" is probably the best sales technique of all.) Set up a fence and this parent, spouse, colleague, or friend sees a barrier erected for the sole purpose of testing his ability to knock it down. Your No is his call to arms; most of us hesitate before we go into battle. It's easy to decide it's just not worth it.

Finally, it may be tough to dish out a No because you can see the hurt it inflicts. Even reflected pain—a wounded look, tears, slumped disappointment—is difficult to bear. That's a No we want to avoid—sometimes when we shouldn't.

All of these may be good reasons why we find No tough to dish out. Tough, but absolutely necessary. Because in the big picture, bottom line, we need to stick up for ourselves. No is the weapon we bring to the party.

There's No free lunch. If you are a person who is naturally open-hearted and generous, No can be an unnatural stretch. If you are one of those who really longs to be liked, it's more than a stretch. It's a cringe. Unfamiliar, uncomfortable but very, very necessary, because constant, craven Yes carves little slices from you, while No is a rock and a shield. Therein lies its power.

Organizational psychologist Adam Grant, author of Give and Take and a professor at the University of Pennsylvania's Wharton School, outs the many professional rewards and successes that accrue to generous givers. Still, Grant emphasizes that "the ability to say No is one of the most important skills one can have, particularly for givers."

Grant points to the power of No as necessary to carve time for one's own goals and agenda. Without it, other people dictate your schedule and limit your accomplishments. Says Grant, "Saying No is especially huge in establishing a work/life balance. Without that ability, work will cannibalize your life."

No also makes other people respect you and your time more, Grant notes. "When you are able to say No, people are careful to come to you with only meaningful requests, rather than simply asking for any help you might be able to give."

No makes your Yes more meaningful, or as Grant puts it, "It makes you more of a specialist, rather than a generalist in what you give to others." When we say Yes thoughtfully, because we are giving in our area of expertise, rather than saying Yes out of a need to be liked, we are far more apt to feel satisfied by giving.

No pays off in the personal arena as well as the professional one. It's exhilarating to feel in charge of one's self, to be the boundary setter and the decider. There's a bonus in energy and .

Too, No tests the health and equity of your closest relationships. If you feel you cannot say No, at least to some things, some of the time, then you are not being loved—you are being controlled.

Finally, and perhaps most important, personal integrity requires the power of No. The ability to say No is an essential element of one's moral compass. Without it, we are merely agreeable pleasers, the Pillsbury doughboys of morals and values. Whatever the cost or quake involved when you deliver a No, backbone is defined by your ability to say it.

Judith Sills, PH.D., a psychologist in private practice in Philadelphia, is the author of Getting Naked Again, Excess Baggage, and other books. Read her PT Blog: Irrational Expertise

Finding Your Voice

OK, No costs. Your payoff in integrity and autonomy, however, is huge. The choice on the table is clear: Strengthen your ability to say No while lowering its cost to your relationships. Several strategies can help you achieve that balance.

Replace your automatic Yes with "I'll think about it."

If you haven't used this technique much, you will be awed by the results. "I'll think about it" puts you in control, softens the ground for No, suggests you are actually weighing important factors, and, most important, allows you the opportunity to think things through. A No that follows thoughtful decision making is a more grounded fence than a No that is fueled by emotional impulse.

Soften your language.

Try "I'm not comfortable with that." "I'd prefer not." "I'd rather..." "Let's agree to disagree here." Or "That's a good/nice/interesting plan, but I won't be able to..." This last is a variant of the Oreo cookie communication strategy, in which you say something positive ("You are such a warm and charming person"), sandwich in the filling of a tactful No ("I don't think you and I have a romantic future"), and then end with another cookie ("I have so enjoyed the time we've spent together; you really make me laugh").

Make no mistake. You are still delivering a clear and powerful No, and the other person well understands that. This No, sweeter and softer, may go down better.

Contain your feelings.

No is best deployed pleasantly with an air of Zen calm. (Tricky, because you are likely feeling very far from it.) Outward calm helps quiet your inner turmoil. What's more, it will reduce the negative impact of your No on the brain of your audience. The jolt that No delivers is big enough without a tsunami of and invective.

Refer to your commitment to others.

Say No without appearing selfish or uncaring by referencing your conflicting obligations to other people. "I'd love to help, but I have already agreed to help my mother/colleague/student then, and I can't let him/her down."

Realize you represent others.

Wharton's Adam Grant suggests that you are likely to negotiate more assertively if you recognize, or even imagine, that you are negotiating a salary on behalf of your family or negotiating a sale on behalf of your company. When it's not just your own interest at stake, you may find it easier to say No to a lowball offer.

Rehearse.

Ongoing situations—a demanding boss who keeps piling on the work, a needy family member who never limits her requests, a mate who badgers until you cave—can benefit from your thoughtful, private rehearsal.

You may design one clear, respectful No and keep repeating it no matter what comes your way. ("I cannot take on another project, Sir, because my plate is too full." "I cannot take on another project, Sir, because my plate is too full.") Repeat politely until the boss finally hears you.

You may practice calmly cutting the conversation short. ("Honey, you and I don't agree on this. Let's close the conversation.") He goes on; you go silent.

Or, if you practice long enough, you might just become strong enough to listen to any inappropriate, uncomfortable, excessive request, pause for breath, and then deliver your one-word, no-explanation verdict: No.