“Do What You Love, Love What you Do.” That’s fairly standard advice these days, whether you’re reading a business magazine, listening to a commencement address or hearing yet another opinion of Steve Jobs’ success. I disagree.

Don’t get me wrong. I enjoy what I do. Marketing is an interesting, constantly changing mixture of art and science. Our company provides products that improve people’s experiences at their respective jobs, and I work with a group of people I enjoy being around. There’s a lot to “like.” And there are many days and weeks when I love what I’m doing. I just don’t think “Loving It” is a realistic benchmark for choosing a career.

It seems I’m not alone. Jason Fried, founder of 37 Signals, wrote in “The Fallacy of Love What You Do” [Inc. Magazine] “…if you want to be successful and make a real contribution to the world, you have to be intrinsically motivated by the work you do, and you have to feel good about spending your days on it. Love might grow–and it’s a wonderful thing if it does–but you don’t need it up front.”

The danger is that the well worn exhortation to “Do What You Love” will leave people dissatisfied, or feeling that they’ve fallen short. Not so! If you have a job that you enjoy, you are good at, and which you are happy at more than 50% of the time, then you’re in good shape.

I can think of three good reasons why “Do What You Love” might not be right for you:

1) You Don’t Have a Passion. I once worked for a very talented guy who was passionate about flying airplanes. I learnt a lot from him, and probably wouldn’t be doing what I’m doing now without his guidance. But one thing he and I could never see eye-to-eye on was the fact that I didn’t have a hobby that I was passionate about. (He never found a way to monetize his passion, though.)

2) Opportunity Hasn’t Knocked Yet. I’m a big believer that – to a large extent – you make your own luck. But timing is also key. Maybe you haven’t yet reached the point you need to be. I started out as a Chemical Engineer at an oil refinery. I didn’t love it, not even a little bit. But that background led to my eventual move to Product Management, then to Marketing. It just took time.

3) Life Gets in The Way. It’s rare that you get to make unilateral choices. Family, finances, and a hundred other factors, are taken into account when you make a decision. Following your passion isn’t always possible or practical. How many people have lost their life savings or ruined a marriage because they insisted on “doing what they love” at the expense of all else?

So, am I telling you to settle for a mediocre life/career? Of course not!

Start with your current job. Find the parts that are particularly rewarding and focus on those; hone your skills; mentor someone in your group; look for ways to expand your influence in areas that matter to you. (Although if you hate what you do, ignore everything else I’ve said and make a change.)

A passion doesn’t have to be expressed at work. Pursue it out of hours. I love traveling, so I take every ounce of time off to explore new places. And I document it with my Canon SLR (another hobby) and hang photos all over the house.

Of course, if you’re one of those lucky people who already “Do What You Love” then Congratulations! Maybe I’ll bump in to you on an airplane soon…