Bad advice is easy to ignore. But sometimes the worst advice can stick with you, as a reminder of what matters most to your personal and professional fulfillment.

Entrepreneurs by definition have to go against the grain, and so conventional, albeit terrible, advice can be used as a motivational tool.

We've collected the worst advice successful entrepreneurs like Mark Cuban and Barbara Corcoran ever received.

Here's what it taught them. 

Shark Tank star and Dallas Mavericks owner Mark Cuban is firmly against the idea of following your passion.

Cuban has said repeatedly that the worst advice he's ever received or heard others receive is "Follow your passion."

"What a bunch of BS," he wrote in a blog post from 2012. Everyone has multiple passions, Cuban says, but those don't lead to career success. What does, however, is finding something to work hard at.

By "following your effort" instead of your passion, you can develop a skill and learn to appreciate it. Your passion for growing tomatoes in your garden can remain a hobby.

Nearly everyone tried to get New York real estate agent Ryan Serhant not to join Million Dollar Listing.

Serhant was a rising star in the New York City real estate industry when he got an offer to be a founding member of Bravo reality series Million Dollar Listing New York in 2010.

He told Business Insider that nearly everyone--friends, family, and colleagues--told him he would embarrass himself on the show, which was probably destined for failure anyway. This turned out to be the worst advice of his entire career, he said.

His boss, Nest Seekers International CEO Eddie Shapiro, was the only person who told him to accept the offer. Not only did the show go on to introduce him to millions of viewers, but his career is also stronger than ever before. 

As an associate broker of Nest Seekers International, he's essentially the CEO of his own independent team, and today the Serhant Team is the No. 1 real estate team by sales volume in New York and No. 6 in the country, according to Real Trends.

Shark Tank star Barbara Corcoran was told she could never succeed on her own.

Corcoran started the Corcoran Group real estate firm in 1973 with her boyfriend, Ramone Simone. In the early '80s, Corcoran told Business Insider, their relationship turned sour and she decided to split the business, retaining her half as the Corcoran Group. Simone was not happy that Corcoran would maintain as much as she did.

"On the way out the door he said, 'You'll never succeed without me,'" she said. Those words were both the worst and, strangely, the best thing he could have said.

"[T]hat was the 'advice' that got me through the thick and thin, mostly because it slammed me in my gut, and I didn't want to let him have the satisfaction of seeing me go down," she said. "That's what I always leaned on when things were bad. I'd be like, 'Damn, I'm not gonna let him see me [like this].'" 

4-Hour Workweek author Tim Ferriss learned a valuable lesson after his guidance counselor told him to not apply to his dream school.

When Ferriss--an accomplished author, investor, and podcast host--was a high school senior, his guidance counselor told him he shouldn't bother applying to Princeton. The counselor was judged on the acceptance rate of his students, and every denial counted against him.

Fortunately, another member of the faculty, Reverend Richard Greenleaf, told Ferriss he had to apply. Ferriss was accepted and would go on to graduate from Princeton in 2000.

Looking back on that, Ferriss told us, he realized two things about advice: 1. Understand other people's incentives when they give you advice. 2. Consider the downside of taking the advice versus not taking it.

Birchbox co-founder Hayley Barna was advised to fundamentally change her company.

"You have to get used to a lot of people giving you a lot of advice when you're starting a business," Birchbox co-founder Barna told Huffington Post Live.

When she and Birchbox CEO Katia Beauchamp started the company in 2010, they were advised to change their company from a monthly subscription service offering a box of assorted beauty products to a service that sent one item weekly, sans signature box.

Not only would that idea not scale, she explained, but it was also one of several examples of an adviser trying to become so involved that the company was no longer the founders' vision.

Best-selling personal-finance writer Ramit Sethi finds it hilarious that tossing out business cards can lead to success.

Sethi is the founder of the personal-finance and career-advice site I Will Teach You to Be Rich and is the author of the 2009 book of the same name.

He once came across the advice that, "If you are hunting for a job, you need business cards in your pocket at all times," so that you can always hand one out to a potential job lead, he wrote on his blog. This is not how you network.

"Yes!" he wrote. "If you've been looking for your Dream Job, the first thing you need is not a strong network, or a process to identify your targets, or a way to narrow down the infinite universe of job options available to you. No, you don't need to understand your psychological barriers, or the interviewing game, or how to master negotiation."

Harry's co-founder and co-CEO Jeff Raider was advised to stick to a traditional career path.

Raider has been fortunate enough to be co-founder of two exceptional startups over the past several years, eyeglass company Warby Parker and men's razor-subscription service Harry's. But when he was still an undergraduate at Johns Hopkins pursuing his bachelors in international affairs, he was preparing to take a much more traditional career path.

"At the time, a bunch of my professors were pushing me to go into diplomacy," he told us. After considering a traditional career path for a successful student in his position, he realized by the time he graduated that he did not want to contribute to the world that way.

"I want to work in a space where there are fewer constraints, where I can constantly push the envelope, innovate, and dream," he said.

Lumo Bodytech co-founder and CEO Monisha Perkash was told she needed to hide the fact that she was a mom to be taken seriously.

Perkash is a two-time entrepreneur, longtime executive, and current CEO of Lumo Bodytech, but she was once told she needed to hide the fact that she was a mom, she told Fast Company.

Someone noticed baby pictures of her child on her screensaver and told her that investors were going to question her commitment to the startup if they ever saw those photos.

Perkash found the idea that a committed leader could not also be a loving mother ridiculous, and has since been comfortable with her life and confident in her decisions.

This story first appeared on Business Insider