There is an Apache legend that the creator gave human beings the ability to talk, to run and to look at things. But in addition, the legend says he was not satisfied until he also gave them the ability to laugh. After giving humans this ability, the creator said, "Now you are fit to live."

A good sense of humor helps to overlook the unbecoming, understand the unconventional, tolerate the unpleasant, overcome the unexpected and outlast the unbearable.

Life is too short to be serious all the time. How dull our existence would be without the potential to see the lighter side of situations. And how hopeless, too! Humor often represents hope -- the idea that the worst is behind us and better things are coming.

True, not all things are funny. Knowing how and when to apply a filter is critical. And it's usually better when the joke is on you, so your obvious amusement signals permission to see the humor in a situation.

"If I were given the opportunity to present a gift to the next generation, it would be the ability for each individual to learn to laugh at himself," said Charles Schulz, creator of the long-running "Peanuts" comic strip.

April is National Humor Month. I would propose that we celebrate humor every single month, all year long. I can't imagine a day without it.

I value a sense of humor very highly when I am hiring people, especially for sales and customer service jobs. My employees know I love a good laugh. For years I started every sales meeting with a funny story or joke, and asked other managers to do the same. I wasn't looking for the next Tina Fey or Jimmy Fallon. I just wanted to loosen up the group and put them in a good mood.

The same attitude is important for anyone who comes into contact with customers. If you've ever flown on a Southwest Airlines flight, you might have heard the safety instructions delivered in a variety of amusing ways. The message is quite serious, but their approach serves a number of purposes: encouraging people to actually listen to what's being said, putting passengers in a more relaxed mood after the stress of airport hassles and letting folks know that the flight attendants are enjoying their work and want you to enjoy your trip.

Did you watch the Super Bowl? Or more specifically, did you watch the commercials? At a cool $5 million for a 30-second spot, the price tag is enough to make a business cry. But year in and year out, the ads command almost as much attention as the game itself -- because they make people laugh. And then talk about them the next day. And buy those products. Beer isn't inherently funny, nor are tortilla chips or car insurance, but, somehow, humor makes those items more memorable.

Some of the funniest people I know are also among the quietest. You have to listen closely to what they say, because the quips sneak out when you least expect them. For example, a woman approached President Calvin Coolidge, aptly nicknamed "Silent Cal," at a dinner and said, "Mr. President, I have a bet with my friend that I can get you to say more than two words." Coolidge replied, "You lose!"

You may think you have to be born funny, but I disagree. Finding the humor in everyday life is easy if you just look for it. People who take themselves too seriously are a constant source of amusement for me. Take this young job-seeker, for example:

At the end of a job interview, the human resources person asked a young engineer fresh out of a top university, "And what starting salary were you looking for?"

The engineer said optimistically, "In the neighborhood of $125,000 a year, depending on the benefits package."

The interviewer said, "Well, what would you say to a package of five weeks' vacation, 14 paid holidays, full medical and dental, company matching retirement fund to 50 percent of salary and a company car leased every two years, say, a red Corvette?"

The engineer sat up straight and said, "Wow! Are you kidding?"

And the interviewer replied, "Yeah, but you started it."

Mackay's Moral: Life isn't always funny, but a sense of humor always helps.

Departing Denver Broncos quarterback Peyton Manning's determination to win Super Bowl 50 against the favored Carolina Panthers was riveting. It reminded me of a quote he gave earlier in his career: "Being there every week for my teammates is really important to me. It's about accountability."

That's discipline, and it's rooted in little things. Isn't everything? Little things sow the seeds. The harvest comes when you can discipline yourself to routinely face life's toughest complications and frustrations. That's a crystal-clear window on the success of the oldest quarterback in Super Bowl history and the only starting quarterback to win with two different teams.

Denver's discipline shone in both directions. Wade Phillips, coordinator of the Broncos' imposing defensive machine, is the son of Bum Phillips -- the former head coach of the Houston Oilers and the New Orleans Saints, who always wore a cowboy hat. According to Bum: "The only discipline that lasts is self-discipline."

Whenever I eyeball the resume of someone applying for a management job, I look for evidence of self-discipline: As candidates have prepared themselves for past jobs, did they identify and master at least three to five key self-disciplines essential to future success?

Did the candidates stick to their routines -- even their daily exercise program -- after suffering a career setback? Dedicated self-discipliners invariably bounce back the fastest.

Does a prospective manager grasp that the self-disciplines needed by the people around her or him probably differ from the ones that bosses master themselves? Managers shore up their strengths with diverse players, not copycats of the head honcho.

Uncommonly strong self-discipline is a hallmark of success in any era. Elon Musk, who's worth a comfy $12 billion-plus, tops today's list for innovative business thinkers. He will turn 45 later this year. After co-founding PayPal, Musk masterminded the product architecture of Tesla Motors, founded SpaceX and provided the initial concept and financial capital for Solar City. Tesla Motors' battery technology has electrified the industry, if you'll excuse the figure of speech. SpaceX is redefining space travel with reusable launch components, and may one day colonize Mars.

Management guru Peter Drucker once quipped: "There is nothing so useless as doing efficiently that which should not be done at all." The relevance? Be careful about those self-disciplines you choose to hammer into habits:

-- These days, everyone is hot to develop abs of steel. Fitness training technologies have evolved like every other discipline. It pays to learn them. If you spend valuable time working up a sweat, best practices produce the premier payoff.

Roy Neuberger, who lived to be 107, made several fortunes, and thereby endowed numerous art museums. At 94, he paid a personal trainer $45 three times a week to help him through a 45-minute workout. At a buck a minute, it helped keep Neuberger spry enough to collect his National Medal of the Arts at the White House at age 104.

-- You may bust your buttons with pride about how regularly you stay in touch with your network, but are you using the cutting edge of social media to do so? Or are you still sending pals press clippings when everyone else is routing them links?

-- I have readers hooked on audiobooks: a great habit to make. If you listen on airplanes, do you also use noise-canceling headphones? A number of physicists and ear doctors point out that these more expensive headsets allow lower-volume playback, and that spares precious hearing.

Be choosy about the number of self-disciplines you adopt. You don't want to morph into a robot. Focus on doing a few well. And always remember: The only way up is up to you.

Mackay's Moral: Long-haul winners listen to their built-in drill sergeant all the way to the finish line.

Over my decades in business, I've noticed a baffling trend: "Sales" has become a dirty word. I'm on a lifelong campaign to change that.

In fact, many companies no longer call salespeople salespeople. They have account executives or account specialists, business developers, client advisers, relationship consultants, territory managers and numerous other monikers. I even received an email from a radio station saying that they call their salespeople business improvement planners.

I'm not sure why the word "sales" seems to have such a negative connotation. I still have "Envelope Salesman" on my business cards -- and am proud of it. Companies cannot succeed without salespeople bringing the business through the front door. It's that simple.

You don't even have to be writing up orders to be in sales, because everyone in the company is selling something -- ideas, customer service, reputation.

You already believe in your products -- or you should -- so that ought to be the least of your challenges. Sales is really about selling yourself! You may not have a formal sales quota to fill, or get paid on commission, but a good knowledge of how to sell can be very useful to your success, no matter what your career goals are.

Here are some sales tips that apply to any endeavor:

-- Manage your time wisely. Keep track of how much time you spend on your sales process. Identify the activities with the greatest payoff and maximize them, while delegating or cutting down on any that don't add value. Remember the 80/20 rule: In many cases, 80 percent of your business comes from 20 percent of your customers. Focus on the 20 percent first.

-- Do your research. Whether you're selling a book or just trying to get a job, start by learning as much as you can about your industry and the people in it. The more you know, the better you'll be able to present your product when the time comes. And don't forget that knowing something about your customer is just as important as knowing your product.

-- Get in front of prospects. Every sale starts with a prospect: a potential customer with an interest in what you've got to sell. Identify those who need what you're offering. Find out where they are so you can target your sales efforts effectively.

-- Listen more than you talk. Don't think of sales as the art of pressuring a reluctant customer into buying something he or she doesn't want. You'll get better results by asking questions about your prospect's problems and really listening to his or her needs. Then it will be easier to position yourself effectively.

-- Get into the customer's mind. You've got to tailor your approach to match individual buyers, not take a one-size-fits-all attitude. Once you've targeted specific prospects, spend some time getting to know their personal priorities, professional preferences and what they're looking for when they consider products like yours.

-- Create the demand. It's not how much it's worth, it's how much people think it's worth. Customers often buy products if they can be sure that product will help them solve a problem, and do it quickly and easily. Show how your product or service will make life easier for the person whose support you need.

-- Stop selling and let them buy. Most people like to buy things, but we really dislike being pushed into a purchase. Don't be overly aggressive. Be ready to answer questions and present your product as an opportunity. Never ask a person a yes-or-no question when it could be yes-or-yes instead.

-- Eliminate the risk. Money-back guarantees and other sales tactics limit the customer's risk of making a mistake. You can't offer a "warranty" on your ideas, but know the risks of your product or service ahead of time, and have solutions ready when you are questioned.

-- Develop your sense of humor. You don't have to memorize a string of stale jokes, but you should learn how to see the humor in every situation. If you can make a customer smile, your job is halfway complete.

-- Follow up. Persistence pays. Don't make a pest of yourself, but check in regularly with your customers and prospects to find out what they need. You don't want them to forget about you.

-- Accept rejection gracefully. Rejection is, and always will be, part of business. The sooner you move on, the sooner you'll make another sale.

Mackay's Moral: Whatever you're selling, you're selling yourself first.