What they smell isn't the emotion of fear. What dogs can smell is the changes in a person's skin that suggest fear to the dog anxiety the way your skin sweats the amount of uric acid that suddenly pours out of your pores.
I wanted to be an astronaut and wanted to go to space camp but then I found out that I was too short to become an astronaut. My mom really made me believe that if I worked hard enough and if I really wanted to do it I could do it.