Needles.
Landing planes. I dislike flying, I don't have a fear, I just don't like it. When you're in the air it's quite lovely, like a train ride in the sky. Unfortunately you have to land, which is another way of saying the pilot feels the need to hurdle the plane toward the ground at an extremely high speed, and then graze the side of the earth with the wheels while decelerating (accelerating at a negative rate for you physics nerds) an an extremely rapid rate. Tell me again why I should feel safe when those seat-belt lights come on?