Want to Be Successful? Have Fun. Seriously. One day I made a promise to myself: If work ever stopped being fun, I would quit and do something else. That promise turned out to be the key to a successful career.

"I just don't get how you can work those crazy long hours like you do," Mike said. "Don't you ever get tired of it?"

"Don't laugh but, to me, this is fun," I told my fellow engineer. "When it stops being fun, I'll do something different. In the meantime, this is it."

That conversation was more than 30 years ago, but I remember it like it was yesterday. It was a defining moment in my career. I wasn't just answering Mike's question but making a life decision, right then and there.

That day, I made a promise to myself: If my work ever stopped being fun, I would quit and find something else to do. I've kept that promise all these years and it's paid off in terms of an incredibly fulfilling and lucrative career.

Don't get me wrong. Not every day, week, or every month is a blast. We all have responsibilities we'd rather not deal with. And there are external factors you can't control. Markets tend to be cyclical, so there will always be tough times. When making important career and business decisions, you have to take the long view.

Related: What Makes a Successful Entrepreneur? Perseverance.

Look at it this way: If your goals are to be financially successful, have a fulfilling career, and live a relatively happy life, of course you have to make some compromises. There will always be tradeoffs. But I'm here to tell you that you can achieve all of that and have fun doing it … but there's a catch. There's always a catch.

The catch is, you have to know your priorities and stay focused on accomplishing your goals. You can't just love what you do. You also have to work hard at it and become very good at it. You have to fulfill your responsibilities and meet your commitments. And whatever you do for a living, it has to be marketable.

If all that sounds like a lot, then you're beginning to get the picture. You're beginning to understand why, if you want to do what you love for a living and have fun doing it, you have to spend a pretty big chunk of your life doing it. And you can't waste a lot of time screwing around with nonsense.

That doesn't mean you can't have a life. I have a great life. But my work has always been an integral part of it, and that's by choice. Being an executive in the tech industry, a management consultant, or a business writer have never been just jobs to me. I love the work. And I actually find news and events related to those fields fascinating. I really do.

That's where this gets interesting. I can't say I've ever given work-life balance a moment's thought. I haven't had to. I'm a hard worker by nature and I like doing things that matter. Some of it I get paid to do, like consulting and writing, and some of it I don't get paid to do, like working around my home and property.

Related: Real Leaders Own Their Mistakes

Sure I have all sorts of interests, but my philosophy on life has always been the same – stay focused on your goals, priorities, and work and have fun doing whatever you do – and I've remained true to that theme all my adult life. I don't think in terms of what I should do, what others do, or how they do it. I couldn't care less about any of that.

Look, this isn't rocket science. It all boils down to one simple concept. If you want to be successful and have fun doing it, you have to make that your main focus in life and stay true to yourself. You can achieve anything, but only by finding your own way of doing things that works just for you and making a promise to yourself to stick with it.

As I always say, nobody ever got anywhere in life by doing what everyone else is doing. Nobody ever made it big by following the crowd. Leaders lead. Followers follow. You can't do both.

Be sure to check out Steve's new book, Real Leaders Don't Follow: Being Extraordinary in the Age of the Entrepreneur. Learn more at stevetobak.com/book/real-leaders-dont-follow/.

Related: Learn to Write, for God's Sake