Shoot for the stars. Follow your dreams. Hard work always pays off. Friends, relatives and mentors are usually the first to spout this advice when you are on the job hunt or considering a new career.

But has that advice gone the way of the dinosaur?

With the fast changing job market, some of this advice no longer applies and could have an adverse effect on your productivity in the long term. We turned to question-and-answer-site Quora for some examples of bad, outdated, or counterproductive career advice. Here’s what had to say about the worst old-school, no-longer-applies advice they’ve received.

Passion? Yeah, right

“Telling people to follow their passions (without any other advice or guidance) simply sends them on a dream chase which may be more harmful to their careers in the long-term,” wrote Colin Shillingford. “Speaking from personal experience, not all of the things I am passionate about are things that I should pursue as a career. One should carefully research a profession before considering a transition into that type of role, because some work seems glamorous or appealing until you are doing it day in and day out.”

Passion it itself is a great thing to have, he wrote, but it “must be accompanied by determination, creativity, talent, and strategy in order to help someone establish a suitable career path.”

Marcia Peterson Buckie said people also need to be realistic. “Sometimes a job is a job and if it doesn't make your soul sing, that's fine,” she wrote. “I think the ‘you must find work you love and makes you feel on fire’ results in a lot of unhappiness and dissatisfaction for people.”

Instead, Buckie suggested finding work you are well suited for “with which you can enjoy a decent quality of life, and has some challenge and reward and fulfilment.”

Sorry, love does not equal money

Ever heard the phrase, “do what you love and the money will follow”? That’s the worst one of them all, wrote Cheryl Woodhouse. “Whoever came up with this clearly didn't understand basic business, or economics,” Woodhouse said. “What if you love drinking beer? Or watching TV? Or hanging out with your friends? I find it hard to believe that someone will pay you for those things.

“And yet even if we specify that ‘doing what you love’ only includes marketable skills, you're trapping yourself. What if you don't love that in five years? One year? Six weeks? You'll be faced with the decision to abandon ‘what you loved’ and change careers, or continue doing something you no longer enjoy,” she wrote.

Another respondent, Tara Orchard, agreed, writing “rarely does that passion equate to a job that will pay the bills. Finding your passion is great, but that does not mean it will lead you to the job you need or even want. Find your passion and find a way to stay connected to it but find a job that you enjoy, do well at and make a contribution. If it is also your passion, that is a bonus.”

Time to move on, really

 “‘Never, ever give up’ is horrible advice,” wrote Jeff Monaghan. “Instead, knowing when to give up and try something else is a key to being successful.

Strengths, weaknesses and all that lies between

Should you really “embrace your strengths”? CamMi Pham said the opposite is often true. “A lot of time embrace your weakness is the best strategy,” she wrote. “Usually your strengths will put you in a box and not many people can overcome it. People start feeling too comfortable and stop fighting.”

When you feel insecure, you have to fight harder to get ahead, she added: “It is a great opportunity for you to innovate.”

‘Work hard and you will be successful’

“Sorry darling, working hard is not enough,” Pham wrote. “Many people work 16 hours a day and they are having hard time feeding their family.” The key to is not to work hard but to work efficiently, she said.

Go to college

School isn’t for everyone. Nor is it for every trade, wrote Armando Martinez Jr. “My wife went to college for five years, she ‘followed her passion’ and now she earns half my earnings, weak benefits and little chance of advancing,” Martinez explained. “I feel like it's partially my fault for advising her to not consider the earnings after college but to focus on her dream.”

It isn’t about what degree you have but who you know, added Pham. “Most successful people are not the most talented/ hard working people. They are usually the most connected people. They know how to sell themselves.”

‘If you are a loyal employee they'll take care of you for life’

Company loyalty is dead. You need to look out for No.1, wrote  Adrienne Flowers. “It's no longer viable to assume you'll find your One True Job and have a straight climb up the ladder with a single company,” she said. “It's no longer reasonable to expect a pension. Loyalty isn't rewarded. No one will take care of you but you.”

It’s all about confidence, baby

How many times have you heard that projecting confidence is key to success?  Maybe it isn’t.

“That ship sailed a long time back,” wrote  Puneet Tripathi. “Had it been 1960s then it would have been enough but now being competent doesn't even pay you nice.”

The answer: You need to be “ravishingly good at it.”

‘Practice makes perfect’

Ed Averbukh called this advice misguided. “If you have no dexterity please don't try to be a surgeon, for the sake of your career and other people's health,” he wrote. “Don't believe the people who tell you that practice makes perfect.”

Practice and training are necessary but not sufficient in every field, he wrote. “You have to have some talent. Practice may improve your ability but it will not make you perfect if there is no talent to begin with.”

What’s the worst advice you’ve been given? To comment on this story or anything else you have seen on BBC Capital, head over to our Facebook page or message us on Twitter.