Unlearning is the new meta-skill. Though it doesn’t get as much attention as it deserves.
You can’t really learn evolution without unlearning creationism (the idea that the Universe was created by a supernatural power). You can’t really learn quantum theory without unlearning that the laws of physics must deal with only those things large enough for us to be able to perceive. 
“All growth requires loss. A loss of your old values, your own behaviors, your old loves, your old identity. Therefore, growth sometimes has a component of grief to it.”Mark Manson
Even though unlearning corresponds to growth, we’re hesitant toward it for the reasons put forth by Mark above.
It obviously isn’t natural for us to question what we believe to be true. But our “truth” can become false as new facts or criticisms against that idea emerge. We can accept or shun away from those criticisms. (“When the facts change, I change my mind – what do you do, sir?”, said John Maynard Keynes.) Even though our instinct doesn’t crave it, we need to value criticisms and other angles over clinging to a (perhaps) false belief of reality we traditionally had.
Unlearning may sound degrading but it’s actually just discarding the erroneous lessons you’d picked up and making room for those that line up with what’s really happening out there in the world. It’s not degrading at all.
Here are 5 common learnings to unlearn to understand what’s really going on:
What most think: “I’ll be happy when…”
What’s really going on: If you can’t be happy with a cup of coffee, nothing ever will make you happy unless you shift perspective.
The “if only _____ were to happen, I’d be happy” thinking is the goal seeking mind which never gets off the hedonic treadmill and that buries our happiness under excuses of getting something or somewhere in the physical world at play.
But that’s not happiness. That’s a way to getting short impulses of pleasure and then the same mood all over again only with a different “if only…” excuse to delay our happiness.
Happiness is a perspective you choose, it unfortunately doesn’t just happen when something “good” happens to you in the physical world.
I go way deeper on the subject of happiness in this post.
What most think: “I know it’s going to continue because it’s always been that way.”
What’s really going on: You can never know for sure.
There’s been this idea of truth for centuries now. That you can know something for sure. That because you deduced x from these true propositions A & B, it is right and nothing can change that.
But you can’t be certain. Knowledge is created to correct errors, not reach ultimate truth. Ultimate truth is not possible. That way of thinking can only ever lead to dogmatism and accepting only a single idea as true and refuting any one that questions it. Something you feel certain about may not be so certain. It’s only when you consider other angles to the problem, or allow for criticisms to be put upon your idea do you come closer to truth.
The idea of induction (“it’s going to continue because it’s always been that way.”) is limited to your observation, and it assumes uniformity of nature to always occur. But uniformity doesn’t work because the only thing uniform in nature is it’s impermanence (i.e. change is a constant).
What most think: “If I get $80 working for 8 hours a day, I can get $100 only by working for 10 hours.”
What’s really going on: Most (non-logarithmic) graphs do not depict straight lines. They come in all sorts of curves and other uncertain patterns.
We assume if things have been going a certain way, that’s how it’s going to continue to be. Or if our wide observation has given us no data whatsoever about black swans, we conclude there exist no black swans. But this is not how the world works.
As instinctually striking as that sounds, upgrading a car from 10 MPG to 20 MPG saves more gas than upgrading from 20 MPG to 50 MPG. As fuel efficiency increases, gas consumption falls sharply at first and then more gradually.  This is a non-linear outcome in action. This is also how stuff works.
Here’s another example: There’s a rule that says, “If a coin has a king on one side, then it has a bird on the other.” Here are four coins displaying a king, a queen, a moose, and a duck.
Which of the coin(s) do you have to turn over to determine whether the rule has been violated?
I’ll let you think…
You probably said “the king” or “the king and the duck”. The correct answer is the king and the moose. Why?
Most know that you need to turn over the king to see if a bird lies on the other side. Queen is out of the question because it specifically says, if king then bird. Duck is not the answer because the rule says if king, then bird not if bird, then king: and even if the duck shared the coin with a queen, our rule would not be violated.
Now, if you turned the moose face and discovered it shared the coin with a king, then our rule would be violated! The answer, thus, is “the king and the moose”.
Don’t be hard on yourself, on average only 10 percent get this answer right. 
Now like you see, things aren’t always top-down in this world.
What most think: “Getting good grades is the most important thing in the life of a student.”
What’s really going on: Grades mess up the whole perspective of learning.
There is literally so much to condemn about traditional education but I won’t go into all of that here.
Just the established idea of education that has crept into society—which puts grades on a pedestal and makes everything else not matter in the face of it—is downright ridiculous. Companies that really understand how the world works have stopped focusing much on the idea of which university the job candidate gets their degree from. Billionaire Elon Musk went so far as to create an exclusive school for his children and those of SpaceX employees (Ad Astra).
The main problem (and there’s quite a lot of these problems) with school is the thinking that comes with it. You don’t want to be thinking like studying only to get good grades, like “learning is boring”, like “whatever is written in the textbook, I need to follow”, like “school comes before play”, like “I need to listen to my teacher and parents even if I feel what they’re saying is not right”, like “my life depends on a piece of paper”.
This is not true education. Preparing kids for writing tests and not for the game of life, that’s a giant pyramid scheme right there we send our kids into.
What most think: “If they’re saying it, it has to be right. We must follow them.”
What’s really going on: They can be wrong and any authority that impresses ideas upon you and does not allow for questioning of those ideas is dogma which is an “undeniable” path to ignorance.
Blindly accepting authoritarian ideas is the root cause for what makes most empires fail to cope when a change occurs. Change is inevitable. And fixed ideas that are not open to criticism and which need to be followed at all costs can be dangerous especially when change occurs because the ideas can turn out to be absolutely, necessarily wrong in those new circumstances.
Authority that impresses certain ideas upon kids should be a legal crime, I feel.
The way to make progress is to question ideas, fine-tune explanations to what’s really going on due to all that criticizing and then creating yet another fallible theory. Make mistakes and correct them. Most just stick with their mistakes because correcting them makes them go against their fixed ideas.
These were just 5 traditional learnings to unlearn. There are many more. But the general idea is to question. Don’t stick with a false idea only because you’ve stuck with it since eternity. As I talk about in this post, question authority and yourself.
Make unlearning a habit (a good one, in a good way).
 Quantum theory isn’t weird, you are. This enlightening post by Eliezer Yudkowsky (from LessWrong) explains why.
 Instinctually striking data extracted from this HBR article.
 This brilliant example was in Steven Pinker’s incredible book Rationality: What It Is, Why It Seems Scarce, Why It Matters. I’d recommend checking it out.