In the last few months, I’ve found myself in dozens of conversations with friends, colleagues and acquaintances who have had tremendous difficulty trying to do what they love.

These aren’t stupid people, and they aren’t just looking to make money. Many of them have worked hard, pursuing degrees in interesting subjects, seeking noble professions, genuinely looking to make a difference. But as they leave school with a degree and a pile of debt, the jobs they want aren’t there.

As they round into their thirties, they find themselves working in jobs doing something very different than they hoped, usually for less money, and usually in fields they aren’t really passionate about. What happened?

I think they were lied to. You can’t be anything you want to be.

Growing up, many of the people around them told them they could be anything they want to be when they grow up. That they should do what they love and the money will follow. That above all, they should do whatever makes them happy. And yet they look at their lives and find it hasn’t worked out the way they planned. They weren’t lied to on purpose, of course. But they were lied to nonetheless.

It’s understandable. Many of the people doling out this advice watched their parents work jobs they hated, come home exhausted, and have very little energy to spend on their families. But I worry that they swung too far in the other direction.

We started to emphasize passion over discipline. Dreaming over doing. Positivity over pragmatism. And the end result was we became people convinced we get to do whatever we want, even if nobody wants it and even if we’re not particularly qualified to do it.

Here’s what we should have been told instead, and what I plan on telling my son.

The market doesn’t care what you love

There are many noble and critically important professions, but there aren’t unlimited roles in those professions. It’s awesome so many people want to teach our kids, but if 100 million people decided they wanted to become teachers, it doesn’t mean the market is obligated to provide 100 million teaching jobs. It’s not a moral or systematic failure on the part of society. While teaching struggles, nursing is growing like crazy. It’s supply and demand in action.

If you’re looking for a job (versus starting your own business), you’re at the mercy of the market. Some trivial professions are grossly overpaid, while many other beneficial professions are grossly underpaid. Some professions have tons of demand, while others have very limited demand. It doesn’t mean don’t get that degree and don’t aspire to that role, but don’t be shocked if the job isn’t there, and don’t be shocked if it pays less than you hoped.

You must create value

Nobody owes you anything. Just because you have a degree doesn’t mean someone is required to give you a job. You must demonstrate you can create value for people, or else they’ll find another person or method to get things done.

Creating value means learning things other people don’t know. It means doing things other people aren’t willing to do. It sometimes means working for free to demonstrate you’re capable of performing. It means taking on tasks no one else wants and turning them into something better. It means working harder than everyone else.

It means demonstrating you’re worth keeping around and worth paying for.

You must be adaptable.

Technology makes it easier for companies to get more work done with fewer people. When this happens, jobs that were once essential become replaceable. If I make a living putting plastic things on the ends of shoe laces, and someone invents a machine that automates the process, and I subsequently lose my job, my company isn’t evil. My company is maximizing shareholder value by creating efficiencies.

Increasingly, the people who stick around are those who learn how to adapt. They don’t lament when they sense the ground shifting beneath their feet. They learn new skills, figure out how to leverage the new tools or take advantage of the new realities. And, when the writing is on the wall and their days are truly numbered, they formulate a plan for landing on their feet.

You must learn how to sell

No matter what my son decides to pursue professionally, I plan on teaching him how to sell. The reality is you’re selling all day long. You’re selling your ideas to your colleagues. You’re selling your abilities to potential employers. You’re selling your vision for the future to your potential spouse. Persuasive people are successful people.

Being comfortable and effective in sales makes you permanently valuable. No matter what the market is doing, there is always a job for someone who can bring in business (or grants, or donors, etc.). Even if your long-term goals don’t involve a direct sales position, it’s an invaluable skill to have at your disposal for when you need it.

You must be entrepreneurial

Once you know how to create value, adapt to changing conditions and sell effectively, you’ll most likely be tempted to go out on your own. And while many of my friends are lamenting their inability to find a job doing what they love, I have many others who realized that they can create their own opportunities.

The truth is entrepreneurship is no riskier than working for someone else. You definitely have short-term risk and won’t be able to pay yourself immediately. And 9 out of 10 companies fail. But the reasons for failing are usually similar to the reasons for not succeeding in the job market – not creating something people value, and not being able to sell effectively.

The upside is you’re not at the mercy of a organization’s budget. There’s no such thing as a hiring freeze. Anyone with some guts can start a company and use the skills they have to create value for customers. You’ll work harder than you ever have, but you’ll be in control of your destiny.

What our kids will know

I think our children will probably learn from our lives. I think they’ll pursue more degrees with practical applications. I think they’ll be extremely entrepreneurial, and will recognize the world changes too fast to stop learning and growing. And I think they’ll know there is no short cut to getting what they want – they have to work really hard for it.

But what about you? I’d argue that it’s not too late to learn these lessons. If you’re 30, you still have 35 years (or more) of your working life ahead of you. Even if the first few years haven’t gone the way you expected, you have plenty of time. But it will take the courage to confront reality – your actual job prospects, your ability to provide for your family in that role, and what you actually bring to the table for employers.