Why? Because they realize happiness is a choice -- and the result of actions, not wishful thinking.

Everyone wants to be happy. Yet many people are not. Is that because of their circumstances, or because of their perspectives?

Great question. Approximately 50 percent of your level of happiness, or what psychologists call your "happiness set-point," is determined by personality traits that are largely hereditary. That means half of your level of happiness is largely outside your control.

That's too bad, but it also means that 50 percent of your level of happiness is largely within your control: health, career, relationships, activities, etc. So even if you were born with a tendency to be at least a little gloomy, you can still do things to make yourself a lot happier.

Like these:

1. Actively pursue your goals.

Goals you don't pursue aren't goals, they're dreams, and dreams make you happy only when you're dreaming.

Pursuing goals, though, does make you happy. According to David Niven, author of 100 Simple Secrets of the Best Half of Life, "People who could identify a goal they were pursuing were 19 percent more likely to feel satisfied with their lives and 26 percent more likely to feel positive about themselves."

So be grateful for what you have, and then actively try to achieve more. If you're pursuing a huge goal, make sure that every time you take a small step closer to achieving it, you pat yourself on the back.

But don't compare where you are now with where you someday hope to be. Compare where you are now to where you were a few days ago. Then you'll get dozens of bite-size chunks of fulfillment -- and a never-ending supply of things to be thankful for.

2. Do what you do well, as often as you can.

You know the old cliché regarding the starving-yet-happy artist? Turns out it's true: Artists are considerably more satisfied with their work than non-artists -- even though the pay tends to be considerably lower than in other skilled fields.

Why? I'm no researcher, but clearly the more you enjoy what you do and the more fulfilled you feel by it, the happier you will be.

In The Happiness Advantage, Shawn Achor says that when volunteers picked "one of their signature strengths and used it in a new way each day for a week, they became significantly happier and less depressed."

Of course it's unreasonable to think you can chuck it all and simply do what you love. But you can find ways to do more of what you excel at. Delegate. Outsource. Start to shift the products and services you provide into areas that allow you to bring more of your strengths to bear. If you're a great trainer, find ways to train more people. If you're a great salesperson, find ways to streamline your administrative tasks and get in front of more customers.

Everyone has at least a few things they do incredibly well. Find ways to do those things more often. You'll be a lot happier.

And probably a lot more successful.

3. Make good friends.

It's easy to focus on building a professional network of partners, customers, employees, connections, etc., because there is (hopefully) a payoff.

But there's a definite payoff to making real (not just professional or social-media) friends. Increasing your number of friends correlates to higher subjective well-being; doubling your number of friends is like increasing your income by 50 percent in terms of how happy you feel.

And if that's not enough, people who don't have strong social relationships are 50 percent less likely to survive at any given time than those who do. (That's a scary thought for loners like me.)

Make friends outside of work. Make friends at work. Make friends everywhere.

Make real friends. You'll live a longer, happier life.

4. Actively express your thankfulness.

According to one study, couples who expressed gratitude in their interactions with each other experienced increased relationship connection and satisfaction the next day -- both for the person expressing thankfulness and (no big surprise) the person receiving it. (In fact, the authors of the study said gratitude was like a "booster shot" for relationships.)

Of course the same is true at work. Express gratitude for employees' hard work, and you both feel better about yourselves.

Another easy method is to write down a few things you are grateful for every night. One study showed people who wrote down five things they were thankful for once a week were 25 percent happier after 10 weeks; in effect, they dramatically increased their chances of meeting their happiness set-point.

Happy people focus on what they have, not on what they don't have. It's motivating to want more in your career, relationships, bank account, etc., but thinking about what you already have, and expressing gratitude for it, will make you a lot happier.

It will also remind you that even if you still have huge dreams, you have already accomplished a lot -- and should feel genuinely proud.

5. Help other people.

While giving is usually considered unselfish, giving can also be more beneficial for the giver than the receiver: Providing social support may be more beneficial than receiving it.

Intuitively, I think we all know that, because it feels awesome to help someone who needs it. Not only is helping those in need fulfilling, it's a reminder of how comparatively fortunate we are -- which is a nice reminder of how thankful we should be for what we already have.

Plus, receiving is something you cannot control. If you need help -- or simply want help -- you can't make others help you. But you can always control whether you offer and provide help.

And that means you can always control, at least to a degree, how happy you are -- because giving makes you happier.

6.Realize that more money won't make you happier.

Money is important. Money does a lot of things. (One of the most important is to create choices.)

But after a certain point, money doesn't make people happier. After about $75,000 a year, money doesn't buy more (or less) happiness. "Beyond $75,000...higher income is neither the road to experience happiness nor the road to relief of unhappiness or stress," say two Princeton University researchers on the subject.

"Perhaps $75,000 is the threshold beyond which further increases in income no longer improve individuals' ability to do what matters most to their emotional well-being, such as spending time with people they like, avoiding pain and disease, and enjoying leisure," the researchers speculate.

And if you don't buy that, here's another take: "The materialistic drive and satisfaction with life are negatively related." Or, in layman's terms, "Chasing possessions tends to make you less happy."

Think of it as the bigger house syndrome. You want a bigger house. You need a bigger house. (Not really, but it sure feels like you do.) So you buy it. Life is good...for a couple months, until your bigger house is just your house.

The new always becomes the new normal.

"Things" provide only momentary bursts of happiness. To be happier, don't chase as many things. Chase a few experiences instead.

7. Live your life the way you want to live it.

Bonnie Ware worked in palliative care, spending time with patients who had only a few months to live. Their most common regret was, "I wish I'd had the courage to live a life true to myself, not the life others expected of me."
What other people think -- especially people you don't even know -- doesn't matter. What other people want you to do doesn't matter.

Your hopes, your dreams, your goals -- live your life your way. Surround yourself with people who support and care, not for the "you" they want you to be, but for the real you.
Make choices that are right for you. Say things you really want to say to the people who most need to hear them. Express your feelings. Stop and smell a few roses. Make friends, and stay in touch with them.

And most of all, realize that happiness is a choice. Fifty percent of how happy you are lies within your control, so start doing more things that will make you happier.

Addendum:

1. 100 Simple Secrets of the Best Half of Life: What Scientists Have Learned and How You Can Use It Paperback – April 5, 2005 ,  David Niven PhD (Author)