Pastels are my favorite medium. Contrary to popular belief, they are not chalks. They are sticks of pure pigment. The same pigment that you would add walnut oil to to make oil paint, or gum Arabic to to make watercolors. Pastels contain just enough binder added to hold them together. A pastel artist is constantly making decisions on how to depict color based on the sticks in the box. Because you cannot mix colors together the way you can with paint, they force my art to be more intentional.
In oil, I often mix the color I see. In pastel I use the lack of the perfect color to push the mood into direction I want my painting to go. An original pastel painting draws you in from across the room and keep you there for a while looking through the layers of color and meaning.