How dare you risk the lives of others so cavalierly
Chicken pox is a virus. Lots of people have had it, and probably don't think about it much once the initial illness has passed. But it stays in your body and lives there forever, and maybe when you're older, you have debilitatingly painful outbreaks of shingles. You don't just get over this virus in a few weeks, never to have another health effect. We know this because it's been around for years, and has been studied medically for years... More here.
This is a BRILLIANT piece of writing which deserves to be read the whole way through. Thanks to Tom.