What does it take to be happy? How do you motivate the people who work for you to do their best? How do you know what is and isn't real in the world around you?

You may think you know the answers to all these questions, but watching the 20 most popular TED talks of all time will likely change your mind. With speakers like Bill Gates and Sting to choose from, some of the highest standards anywhere, and a proven method for mining the best and most insightful information any speaker can share, by the time a talk is published on the TED website, it's always worth watching and almost always brilliant.

Just how great does a talk have to be to shine in that high-level group? Take a look at these examples and you'll know. They are not only entertaining and thought provoking, but will likely make you rethink many of your assumptions. Here are just a few beliefs that these talks may unsettle:

1. Getting what we want will make us happy.

Not by a long shot. After explaining how making his younger sister think she was a unicorn kept her from feeling pain after a fall, psychologist Shawn Achor explains how the external facts of our lives account for very little of our actual happiness. And Harvard psychologist Dan Gilbert shows us how we can be happy even when everything goes wrong.

2. The best leaders create great incentives.

You might think that figuring out how to give employees the rewards and accomplishments they're looking for would be the best way to create an effective organization. In fact, leadership expert Simon Sinek and the legendary Tony Robbins each explain in different ways that answering the question "Why?" is infinitely more powerful.

3. Some people are more creative than others.

And you need those people on your team, right? It turns out that employees' creativity has everything to do with how you motivate them--and the traditional forms of motivation are dead wrong, according to career analyst Dan Pink. Not only that, Eat, Pray, Love author Elizabeth Gilbert makes the case that, rather than a few people "being" geniuses, all of us "have" genius within us.

4. Power equals strength.

Actually, the happiest, most joyful, and most fulfilled people are those who are willing to let their worst weaknesses show, argues social researcher Brené Brown. Not only that, but power is largely a matter of your own perception. And--surprisingly--you can change that perception simply by altering the ways you sit, stand, and move, explains social psychologist Amy Cuddy.

5. The world is as we see it.

Or maybe not. Underwear model Cameron Russell does a quick change onstage and reveals a lot about how the images we see in magazines and in the media bear little or no resemblance to the humans being photographed. "Brain magician" Keith Barry shows us how easily we can manipulate our own perceptions. And in an incredibly moving talk, brain scientist Jill Bolte Taylor experiences a stroke and gets to find out firsthand how the right side of our brains perceives the world.