Like so many others in business, I have accumulated my share of enemies over the course of a lifetime. It's nothing to be ashamed of. "Forgive thy enemies" is difficult advice for many of us to follow. After all, if we feel people have harmed us, we tend to want to get back at them. As a result, we can carry our grudges for many, many years.

And, of course, it is totally counterproductive. I once fired an employee who then went into competition with me and began using what I felt were unfair business tactics. The psychic energy and accumulated bitterness that went into my thoughts of revenge consumed me for the better part of five years.

It was more than a waste of time, because whenever I thought about it, I grew vindictive and sour, and those attitudes spilled over into everything I touched. As a result, I lost more than the object of my revenge. Something had to give. And that something was me.

If you can't take the best advice and forgive your enemies, then take the second-best course and forget them. The only way you can achieve true revenge is to not let your enemies cause you to self-destruct.

I learned a similar story from Bernie Marcus when I was interviewing 29 people for my book "We Got Fired! ... And It's the Best Thing That Ever Happened to Us." In 1978, Bernie was fired as the CEO of Handy Dan Home Improvement Center chain by Sanford C. "Sandy" Sigoloff, who ran the parent corporation, Daylin. Bernie was 49 years old and had never been fired before. He called it "the low point in his life."

Bernie was wounded and aching. His first and only thoughts were about getting even.

"It's interesting when you have a low like this, you reach one point where you have a chance of coming out or not coming out," he said. "If you come out, you're better than you ever were. If you don't come out, you become what they commonly refer to as a 'loser.' If you come out, it's usually because of the influence someone has on you."

Fortunately for Bernie, that influence was Sol Price, founder of Price Club, which has since become part of Costco. Price phoned Bernie and invited him to dinner at his home in San Diego.

Bernie got right to the point: "My contract with Daylin was worth a million dollars. Sandy broke the contract. I want to get back at him. Right now I'm suing Sandy for that million."

To wage the suit, Bernie said he was eating up cash like it was going out of style. Price understood, and the strategy he offered was truly priceless.

After dinner, Price took Bernie to a room in his house filled with papers stacked five to six feet high and no furniture. They were all depositions from a lawsuit Sol had been involved with. He told Bernie that the lawsuit consumed much of his energy and strength for three years of his life.

Price told Bernie: "Why are you spending your young life suing somebody? Why don't you just forget about it and go on and live your life? Otherwise, you're going to end up with a room like this."

The next morning when Bernie woke up, he said he "really woke up. I called the attorneys and said, 'You're off the case. End the litigation. I'm going on with my life.'"

Just where did Bernie go? One year later in 1979, he and Arthur Blank launched The Home Depot, which became the fastest growing retailer in U.S. history.

You will never get ahead of anyone as long as you are trying to get even with him because in order to get even with him, you have to stoop to his level. If you didn't like their tactics, why would you want to emulate them?

I am not in any way advocating being a patsy for another's bad behavior. But you must weigh whether bringing another person down will lift you up. Take the high road whenever you can -- it's usually not too crowded.

You must also consider what exacting revenge does to your physical and mental health. Will it really make you feel better? Consider the words of Martin Luther King Jr., an advocate for forgiveness and peace: "The old law about 'an eye for an eye' leaves everybody blind."

Mackay's Moral: Revenge may seem sweet, but it makes for a sour disposition.

I hate to lose. And that is how Nick Bollettieri became my friend.

When I was in my early 20s, I gave up my dreams of becoming a professional golfer. Actually, I am a pretty good golfer, but I knew that I wasn't going to be the next Arnold Palmer. Eventually I decided to seriously pursue the game of tennis. And I wanted to be really, really good.

I headed to Dorado Beach, Puerto Rico, in the early 1970s for some lessons with Nick. From the moment I gripped my racquet, I knew the ball was in my court. He worked me harder than I ever thought possible. As a coach, Nick is feisty, combative and one of the greatest motivators I've ever met. He always delivers more than he promises.

For those not fortunate enough to have worked with Nick, I am pleased to share news of his terrific new autobiography, "Bollettieri: Changing the Game." You needn't be a tennis lover to benefit from his story. Nick is a master motivator and one of the most competitive people you'll ever meet. He has dominated the field of sports training for five decades and is still going strong.

What makes an icon? What makes a one-in-a-million coach? What fuels his intensely competitive spirit? And what on earth keeps this 81-year-old so invulnerable to the challenges of a few decades?

The answers to all those questions start and end with one single trait: He has always been determined to be the best he could be. Nick could have entered any profession and he would have been a superstar.

The clinics he has conducted around the world are legendary. People of all ages and skill levels flock to his academies, now part of IMG Academy. Nick has coached and developed 10 No. 1-ranked players: Andre Agassi, Jim Courier, Boris Becker, Monica Seles, Serena and Venus Williams, Martina Hingis, Maria Sharapova, Marcelo Rios and Jelena Jankovic.

Nick does double duty as a coach, both for the player and the parents of his prodigies. He defines the complex relationship: "The player can't be successful without player/parents/coach understanding each other's roles."

He founded the Nick Bollettieri Tennis Academy in 1978, the first full-time tennis boarding school to combine intense on-court training with a custom-designed academic curriculum.

Teaching such a diverse group of students at so many skill levels requires a multi-dimensional approach. His secret? Find the idiosyncrasies of each individual and then work from there. His methods have been the secret to his success for 55 years of teaching.

Nick's total package blends technical and strategic on-court training with specialized performance physical training and mental conditioning. His goal is to go beyond training just the physical aspects of the game. He aims to prepare his students for a successful life off the court as well. His college major in philosophy creeps into lessons and long-term thinking.

Nick was a pioneer in the field, which means he took the arrows that go along with the territory. His vision wasn't shared by his peers (if he actually has any), and the critics didn't hold back. Then they saw his results. The noise eventually died down. As Nick says, "You don't coach skills. You coach people."

Nick demands the best from his students because he only gives them his best. He doesn't settle for average from anyone. Nick produces champions because he is a champion himself, and his students are the big winners.

He has established fabulous inner city youth programs for minority youth. Nick understands that they don't pay off on effort; they pay off on results. In my own hometown of Minneapolis alone, Inner City Tennis touches the lives of about 5,000 kids every year, as well as the 100-plus volunteer senior citizens who, as coach/mentor/tutors, build an intergenerational rapport with these children. The program focuses on the development of these young people in specific characteristics such as responsibility, respect, teamwork, enthusiasm, integrity, perseverance and service.

By the way, it is the only board that Nick has ever agreed to serve on, even though he has been asked to join hundreds.

Nick's story is well worth the read. Just as with his coaching, he doesn't hold back.

Mackay's Moral: Nick Bollettieri is a game changer -- he serves up aces from which we all can learn.

A man walking down a narrow, twisting road spotted a guru meditating on the grass.

"Excuse me, master," he called. "Is this the road to success?"

The old man nodded silently and pointed a finger in the direction the traveler was headed. He thanked the guru and hurried on his way. An hour later the man returned, bleeding and exhausted.

"Hey!" he shouted to the guru. "You told me that was the road to success! I walked that way, and right away, I fell into a ditch so deep it took me almost an hour to climb out! What's the matter with you?"

The guru stared at him, and then after 10 long seconds opened his lips to speak: "That is indeed the road to success. It lies just beyond the ditch."

The road to success is not without potholes. That's the problem with many of us. We quit before we find success. We let challenges beat us rather than rising to the occasion. We see only the difficulties in front of us, but not the opportunities that can grow from them.

My own formula for success includes:

-- Dogged determination.

-- Focus and the ability to finish.

-- Daring to dream.

-- Owning and learning from mistakes.

-- Looking at problems as opportunities.

-- Staying positive.

When Dale Carnegie was asked on a radio program to tell in three sentences the most important lesson he had ever learned, he said: "The biggest lesson I have ever learned is the stupendous importance of what we think. If I knew what you think, I would know what you are, for your thoughts make you what you are. By changing our thoughts, we change our lives."

In other words, the will to succeed very often determines our success.

Another important part of success is just getting out of bed. Benjamin Franklin pointed out that early to bed and early to rise can make you healthy, wealthy and wise. Unfortunately, the "early to rise" part is a problem for many people.

But if you want to get a good start on the day, you can't sleep your life away. I've found that if you establish a routine and get up at roughly the same time every day, your body wakes itself up. Give yourself a reason to get up. Pick something you're passionate about to work on first. You'll find it easier to get out of bed when you've got something exciting to look forward to. And you will most likely find it easier to achieve if you love what you do.

Being good at your job is only part of the recipe for success at work. You must also incorporate these key ingredients:

-- Positive attitude. Managers and co-workers alike appreciate the support of someone with an upbeat outlook. Don't hide your enthusiasm for your job and the organization you work for. Look for opportunities that arise from problems. Challenges help you grow.

-- Integrity. Be honest with people. When you don't have an answer, say so. Admit your mistakes (and concentrate on not repeating them). Keep your promises, and meet your deadlines. All this demonstrates your respect for other people and proves your reliability.

-- Willingness to try. Stretch out of your comfort zone. Volunteer for new tasks and extra responsibility. Take risks -- be realistic about what you can and can't do, of course, but don't back away from a challenge because of the possibility of failure. Ask the right questions so you understand the situation. Never be afraid of asking a "dumb" question. Be more concerned about having to claim ignorance after the fact.

-- Cooperation. Be a team player. Help your colleagues with their priorities. Share information instead of hoarding it. Know what your manager wants, and support him or her to the best of your abilities. Offer your support when people need it. When your team is successful, you are successful.

A wise man was counseling a young graduate who was preparing to start a new life. He said, "Remember there are three bones, and you will never have any trouble."

"How will three bones keep me out of trouble?" asked the student.

The elder explained: "There is a wishbone, a jawbone and a backbone. The wishbone keeps you going after things. The jawbone helps you find out how to go after them if you are in doubt, and the backbone keeps you at it until you get there."

Mackay's Moral: Success is sweet, but its secret is sweat.