Ask just about any motivational speaker or career expert. Or ask Steve Jobs:  As the Apple co-founder once said, "You've got to find what you love. The only way to do great work is to love what you do. If you haven't found it yet, keep looking."  

Most people believe passion comes first.

But not Mark Cuban. When Adam Grant asked him if there was a "worst piece of career advice you've gotten," Cuban said:

Follow your passion? No.

Follow your effort. No one quits anything they're good at.

While passion can spark effort, the reverse is more often true. Effort, and the improvement that results, creates passion. Do something poorly? You probably dread doing it. Do something well? You enjoy it -- and the better you get, the more you like doing it.

Science agrees, especially where starting a business is concerned. According to a study published in Academy of Management Journal, the more effort entrepreneurs put into their startups or side hustles, the more enthusiastic they get about their businesses

As startup founders gain skill, expertise, and experience, their enthusiasm grows -- with or without early financial success. Effort, and resulting improvement, creates passion.

Not the other way around. 

'Follow Your Passion' Can Be Disastrous

It's easy to confuse a hobby or interest for a passion, especially one that will result in career or business fulfillment. Rarely is that type of preexisting passion valuable. 

As Cal Newport writes in So Good They Can't Ignore You: Why Skills Trump Passion in the Search for Work You Love, "Telling someone to follow their passion can be disastrous. That advice has probably resulted in more failed businesses than all the recessions combined, because that's not how the vast majority of people end up owning successful businesses."

That's because most passions indicate interest, not effort. Plenty of people -- maybe you're one of them -- are passionate about sports. Or adventure. Or travel. I enjoy motor sports, and I really like driving -- or riding -- fast.

But how much effort do you, or I, put into that passion? How much effort do we put into improving our talent, our knowledge, and our skills? In my case, not a lot. Passion only indicates interest.

Instead, 'Follow Your Effort'

Passion is nearly always the result of significant time and effort, because effort leads to improvement and expertise. 

As Cuban wrote on his blog in 2012:

There are a lot of things I am passionate about. [But] the things I ended up being really good at were the things I found myself putting effort into. A lot of people talk about passion, but that's really not what you need to focus on.

... when you look at where you put in your time, where you put in your effort, that tends to be the things that you are good at. And if you put in enough time, you tend to get really good at it.

If you put in enough time, and you get really good, I will give you a little secret: Nobody quits anything they are good at, because it is fun to be good. It is fun to be one of the best. 

But in order to be one of the best, you have to put in effort.

What you do in your spare time -- not passively experience, but actively do -- clearly indicates an interest. As Cuban would say, you're already putting in the effort. 

So follow that effort. Every highly skilled person started learning, and then benefited from the virtuous cycle of effort and achievement: Effort leads to achievement, however small. Achievement feels good. Feeling good motivates you to put in more effort, leading to more achievement, more motivation, more effort--the result is a never-ending virtuous cycle.

Follow your effort, and place a little more structure around the process of improving, learning, and growing. The more effort you put in, the more enthusiastic you will get. The more passionate you will become. The more likely you will be to develop the talent and experience required to turn a passion into a new business or career. 

One where passion is not required, because in time you'll realize you're doing what you love. 

Even if it didn't start as a passion.