Speaking to entrepreneur and VC Randall Kaplan on his podcast, In Search of Excellence, the Dallas Mavericks owner added individuals are completely in control of the single habit that will make them a winner.

“The one thing in life you can control is your effort,” said the man worth $6.6 billion, according to the Bloomberg Billionaires Index. “And being willing to do so is a huge competitive advantage, because most people don’t.”

Effort isn’t just simply turning up on time, Cuban says, it’s proactively problem-solving and going above and beyond the requirements of your role.

“There’s some people, or employees, that if you tell them to do A, B, and C, they’ll do A, B, and C and not know that D, E, and F exists,” Cuban explained. “There [are] others who aren’t very good at details: If you tell them to do A, B, and C, all they want to do is talk about D, E, and F.”

If they’re not willing to put in the work? “Don’t apply for a job with me,” Cuban said.

It’s good to hate your boss

They say that the number one reason people leave their jobs is their manager—but according to Cuban disliking your boss can actually be a boon.

The serial entrepreneur had some brutal news for people struggling with their managers, telling them they need to learn from their boss’s mistakes instead of throwing in the towel.

On the podcast Cuban recounted the explosive relationship he had with a boss early on in his career at Mellon Bank in the 1980s.

Explaining how the pair had disagreed over Cuban’s proactive nature, the Dallas Mavericks owner said it taught him a great deal about how not to behave, a key skill for aspiring managers and entrepreneurs.

Cuban acknowledged it can be tough if you don’t like your boss but said disgruntled employees needed to reframe the situation as a learning moment, grit their teeth, and get on with it.

“There’s two things to consider: One is always realize you’re a free agent; you’re allowed to look for your next job while you’re in your current job,” the Cost Plus Drugs founder began.

“But more importantly—and this particularly applies to your first job—is that in college you paid to learn, but now that you’ve graduated you’re getting paid to learn. Take advantage of the ‘to learn’ part of it.

“That’s where people who are in jobs they don’t like make a mistake. They’re so miserable they just can’t wait to get out, and they don’t realize that you can learn more from the jobs you don’t like than the jobs you do like.

“Learning what not to do is just as critically as important as learning what to do—particularly if you have any aspirations to go on to management or to launch a company.”

He added that at the jobs and companies that hadn’t worked out for him, he’d learned “as much, if not more” than the employers where he’d had a positive experience.

Cuban said working a job you don’t like is like attending a class at school you don’t enjoy: “If you really make an effort to learn, not just, ‘I’m an accountant; I’m counting rolls of carpet for an audit,’ but ask, ‘How is the company run? How are managers managing? If I don’t like my boss—why? Is there a way I can communicate with that boss that makes me better at communicating?’

“Learn from what they’re doing so you don’t do the same when you become a boss.”

Early on in careers it can be “hard to have that perspective,” Cuban added, but said: “Look at your ultimate goal, and within the context of that ultimate goal, what can you learn for your current set of circumstances?”