You? Or your child? For children, chicken pox is a nuisance but not a major harm. And it creates a lifetime immunity. But if an adult comes down with it, it can actually be deadly. But by getting an immunization, you can avoid even the aggravation of a mild disease, but better, you can eliminate the possibility of contracting a deadly disease later in life. A shot is essentially the same as getting the illness without going through the entire process and aggravation of the illness.