Scientists know the decision you're going to make 6-seconds before you ACTUALLY make the decision. Maybe it's just me, but that is NOT a pleasant thought.
As a human, I pride myself on being independent and having the freewill to make my own decisions. America itself is built on the idea that there are fundamental freedoms that all human beings have, and that includes making their own decisions. But the idea that someone else's conscious could know your decision before you yourself know it, is a hard concept to grasp. According to experimenters, there's a certain amount of brain activity that occurs before we make a decision. An increase of a certain area's activity can tell scientists whether you're going to choose right or left, up or down, etc. This gives them a head start, on your consciousness, to what the decision you have made is.
Mathematician Marcus de Sautoy made the conclusion that our conscious actions are actually SECONDARY to our brain activity. Although our consciousness are our lives, the activity occurring in our brain determines the decisions we make. Our brain activity and conscious minds are connected, which helps our brain activity recognize certain aspects of our personalities. Because of this connection, our brain activity isn't as likely to make a decision that your conscious self would be appalled by. Our consciousness is our brain activity, and that is what controls our lives.
Personally, I never thought the idea of making decisions needed or could be explained by science. I always imagined our decisions are based on our past experiences, which are just memories and lessons stored in our minds... But I stand proven wrong by Science.