Chickenpox is a form of herpes and we all have it. What matters is that it's harmless.
There are cases of herpes causing death. For example, in an infant infected by his mohel, and a laboratory researcher killed after exposure to monkey feces. (http://www.cdc.gov/mmwr/preview/mmwrhtml/00056008.htm)
The reason medical professionals recommend parents let their children catch chickenpox is because it the symptoms get worse the older you are. In your later years it can even be life-threatening. Never underestimate the chickenpox!