We all like to think we’re in control of our own decisions, right?

Think again. Behavioral economist Dan Ariely does a scary-good job of calling that into question in the video below. Many times we have the illusion that we’ve made our own decision when the decision is actually influenced by someone else, Ariely tells us.

If you’re in a leadership position – or you just want to better understand your own decisions and the decisions of those around you – this video provides some fascinating and hilarious insight.

One of Ariely’s examples: organ donation. When asked to check a box at the DMV if they want to be a donor, the vast majority of people don’t check the box and do not become donors. When the box says to check if you do not want to be a donor, same goes: Very few people check the box. But, in that case, not checking means becoming a donor. Ariely’s point is that most people walk into the DMV thinking they’re in charge of whether to become an organ donor. But the person who’s really in charge is the person who designed the form.

If you’re not familiar with Ariely, he’s a fascinating guy. The researcher and Wall Street Journal columnist became interested in irrational behavior came many years ago while recovering from severe burns sustained in an explosion.

“Upon leaving the hospital, I wanted to understand how to better deliver painful and unavoidable treatments to patients so I began conducting research in this area,” Aerily says in his bio. “After completing this initial research project, I became engrossed with the idea that we repeatedly and predictably make the wrong decisions in many aspects of our lives and that research could help change some of these patterns.”

The video is full of other mind-boggling examples that will change the way you think about who’s in control of your decisions. It’s long (17 minutes) but worth the time. It has amassed nearly 2.5 million views since it was posted in 2009.