I think the biggest problem people have when drawing with crayons is that they regress to being five years old again. They hold the crayon like they're coloring again, instead of applying it like a fine art medium. Another problem is that many people want to make it perform like colored pencils. While similar in application, they are quite different. You should not use crayons and expect them to behave like colored pencils. You'll be setting yourself up for disappointment.
Psychologist Gloria Martinez Ayala tells the Huffington Post that coloring triggers and stimulates the brain areas associated with motor skills, creativity, and the senses. Coloring helps to calm the part of our brains called the amygdala, which controls our emotions and stress. Simply put? Coloring takes our minds off our problems, and as a result leaves us feeling much more relaxed, rested, and at ease. Furthermore, experts say that concentrating on a coloring book lets us mentally escape by bringing back memories of childhood, a less stressful time for many of us.