U.S. President Harry S. Truman once said, "A pessimist is one who makes difficulties of his opportunities and an optimist is one who makes opportunities of his difficulties."

Which do you think will reach their goals, live a happy life and achieve their dreams?

Imagine interviewing two people who have identical skills, but one is always grumbling about how unfair life can be, while the other one talks about what wonderful possibilities exist. Whom would you want to hire? Whom do you think would do a better job?

Naturally, you would gravitate toward the optimist. If you choose the pessimist, you would be setting yourself up for plenty of aggravation and disappointment, not to mention the negative impact on your staff and customers. Pessimism can bring everyone down, not just the person with the negative attitude.

Pessimism is nothing more than self-sabotage. Expecting only the worst is not being realistic. Realists hope for the best but prepare for the worst. Pessimists can't imagine the best, so only prepare for the worst.

And then if the worst never happens? Pessimists often find the worst possible result simply to prove that their concerns were right.

The question becomes, would you rather be right than happy? That's not being realistic either. That's being self-defeating. Pessimism can rob you of your energy, sap you of your strength and drain you of your dreams.

Optimism is the remedy. Optimism doesn't mean pretending life is always wonderful. Optimism means embracing reality. You accept that there will be bad days, but also good days. When you're grounded in reality, you know where you are and how far you need to go. Once you know how far your goal may be from where you are, optimism can give you the motivation to make plans to get to where you want to go.

Pessimists see life as one problem after another. Optimists see life as one opportunity after another.

How you look at life can drastically affect how much you enjoy your life. Optimists expect the best out of life. If you were not raised with this attitude, take comfort: It can be learned.

Optimism is based on three basic tenets, according to Mary Kay Mueller in her book "Taking Care of Me: The Habits of Happiness":

-- Bad things do happen in life, but they are temporary.

-- Bad things in life are limited in scope and tend to be small or insignificant.

-- People have control over their environments.

Pessimists reverse the tables:

-- Good things in life are temporary.

-- Good things in life are limited -- small or insignificant.

-- People have no control over their environments.

Does it make sense that pessimists tend to blame others or circumstances for their failures?

Optimists help create some of the good they come to expect, so they are probably right more often than not -- and they don't waste time worrying about what they're not right about. Optimism relaxes people. When we're relaxed, there is better blood flow to the brain, which results in more energy and creativity in your life.

Consider how optimism turned this situation around:

Over the course of seven years, a woman's mother died, her husband divorced her, and she found herself living in poverty, just one step away from being homeless. In her spare time, she wrote a book that 12 publishers rejected. Finally one publisher accepted her book about a boy named Harry Potter. And then she wrote a few more books, which became blockbuster movies, and even spawned a theme park.

J.K. Rowling was an optimist who's now a billionaire. How far in life would she have gotten by being a pessimist?

There is virtually nothing that you can't do if you set your mind to it. You cannot control events in your life, but you can control how you react.

Do you want to be a pessimist and have no hope for a better future? Or would you rather be an optimist and believe you can achieve a better future?

There once was an old man who had many troubles. No matter what hardship life handed him, he faced each obstacle with a smile and a cheery disposition.

A friend finally asked him how he managed to stay so happy despite his challenges.

The old man quickly answered: "Well, the Good Book often says, 'And it came to pass,' but never once does it say, 'It came to stay.'"

Mackay's Moral: Attitude is the mind's paintbrush -- it can color any situation.

I recently came across a graduation speech by the valedictorian of a university law school. He began his remarks by acknowledging that he had difficulty deciding what "wisdom" to impart to his fellow graduates. He said he had consulted several quotation books and speaker's guides, but had come away uninspired. He reviewed all the cases of law the class had studied and had found nothing that he felt was appropriate on such an important occasion.

At a loss for any inspiring thoughts, he sat down at his kitchen table to eat biscuits. And right in front of him on the opened roll of refrigerated biscuit dough, he spotted the belief that he knew he and his fellow graduates had in common and that he felt was worthy of the occasion. The package, he said, had this message: "Keep cool. But do not freeze." And with that he thanked all assembled and returned to his seat amid rousing applause.

Freezing up -- also referred to as choking -- in important situations happens to all of us. We regularly hear about golf superstars who blow a tap-in putt or $16 million-a-year basketball players missing a crucial shot.

Choking also happens many times in business. How about the seasoned sales rep who botches a million-dollar sale? Or the customer service rep who makes a problem worse rather than fixing it?

Many times choking is triggered by thinking too much. Now neuroscience explains why. We used to assume that if the incentive is increased, the will to perform will automatically increase as well. Not so, according to a study that appeared in the journal "Neuron."

A simple arcade game was used for the test. At first, performance steadily improved as incentives increased. The extra money proved motivating. But this effect only lasted for a little while. Once the rewards passed a certain threshold, scientists observed a surprising decrease in success. The extra cash hurt performance, and the subjects began to choke. Brain activity became inversely related to the magnitude of the reward. Bigger incentives led to less excitement.

The study stated that: "The subjects were victims of loss aversion. That's the well-documented psychological phenomenon that losses make us feel bad more than gains make us feel good. Instead of being excited by their future riches, the subjects were fretting over their possible failure ... they care too much. They really want to win, and so they get unravelled by the pressure of the moment. The simple pleasures of the game have vanished ... The fear of losing is what remains."

That attitude is completely counterproductive. One of my favorite aphorisms is, "If you want to triple your success rate, you have to triple your failure rate." Fear of failure is paralyzing. It prevents you from taking the risks necessary to succeed spectacularly.

If you choke when you're in the spotlight or you start shaking, blushing or having shortness of breath when you're on stage, check out the story by Karen Haywood Queen in Better Homes and Gardens about pianist Miriam Elfstron. Elfstron suffered the jitters so bad that she had to wear mittens all day the days of her performances because her hands shook and became cold. Eventually, her piano instructor taught her how to control her anxiety. Her recommendations included:

-- Think positively. Practice making positive statements about what you are doing and avoid using negative words or self-talk. For instance, say, "I am confident," not, "I don't feel nervous."

-- Practice performing through the inevitable slips. It's a performance. If you mess up, the world won't come to an end. Get comfortable recovering from slips and memory lapses.

-- Practice in front of smaller groups first. Don't perform for the first time for a crowd of 500. It's too much pressure.

-- Reduce muscle tension to reduce mental tension. It's all connected, so if your body is relaxed, there's a good chance your mind will be relaxed as well.

-- Adopt a ritual. Carry a lucky charm. Wear your lucky shoes. Touch your nose before you begin. Dribble the ball three times before the game starts, like Michael Jordan. Whatever works for you is OK.

-- Don't be a perfectionist. Don't visualize a perfect performance, because then you will feel like you've failed if you make even a small mistake. Instead, picture a performance where you do well by overcoming small obstacles along the way.

Mackay's Moral: Don't let choking suck the life out of your career.

A couple years ago, I wrote two columns on street smarts that really resonated with readers. They asked for more!

Drawing on what I've learned over many decades in business, I just barely scratched the surface. These are little nuggets that you probably won't learn from a book in school, but they are important for success. Here's Part 3 of Harvey's Street Smarts:

First idea: Make gifts memorable. Use creative gifts to stand out and be remembered. I also appreciate gifts that continue to remind me of that person. For example, a clock that chimes.

Next idea: Humanize your selling strategy. Learn what people's hobbies are and find ways to leverage them through tickets, clippings or just current conversation. Learn what turns a person on.

Next idea: You're not just selling a product. In every sales transaction, position yourself as your customer's confidant and adviser. More than product, you are selling trust first and foremost.

Next idea: At every meeting with managers, always go around the room and ask managers what can go wrong and prioritize it. If it happens, how are we going to solve it?

Next idea: Hold one-on-one meetings with your employees to learn all about them -- what is important to them at work and at home. Employees are people first!

Next idea: You want to make every customer feel like he or she is the only customer you have.

Next idea: Timing is everything. You never ask your parents for the keys to the car when they are in a bad mood.

Next idea: You can't successfully negotiate anything until you know the market. You won't recognize a good deal unless you've done your homework.

Next idea: You always want to sleep on it. Take your time in most decisions and things become much clearer.

Next idea: Never say no for the other person. Ask and let them say no.

Next idea: Short notes yield big results. It takes only a moment. As a matter of personal recognition and courtesy, remember names and take a personal interest in people.

Next idea: When you boil it all down, the world of business really rotates on the following principle: Every person needs someone else to help them open doors. And that can only be accomplished -- no matter what you are selling -- by a phone call, email, letter or in person, giving that individual instant credibility to make the contact.

Next idea: Outside my office door is a sign -- If you know where you can get us some business, come on in. On the table is a sign -- Our meeting will not be interrupted unless a customer calls.

Next idea: Every person basically knows about 200 people, so if you have 10 friends, you have 2,000 contacts. If you are lucky enough to have well-connected contacts, you could start out with many thousands more. Remember that you are seeking quality, not quantity.

Next idea: Friends of comedian Red Buttons thought he had a phenomenal memory with holiday cards. He filled them out year-round when he met people and mailed them at Christmas time.

Next idea: Never tell a mother her baby is ugly. When someone is close to a project, be very careful what you say. It may come back to bite you.

Next idea: Every day of your life, you have to get up and do a couple things that you don't want to do. So you might as well get on them right away in the morning.

Next idea: You can take any amount of pain, as long as you know it will end. Some days will be bad, but the sun will still rise the next morning.

Next idea: Introduce yourself to every person you sit next to on an airplane or anywhere else. The person on your left or right or in front or back of you can be very important in your life. Do not judge a book by its cover.

Next idea: Knowledge is power -- but not until it is used. Information is only as good as what you can do with it.

Mackay's Moral: Stay on your toes or fall flat on your face.