I once crashed without a helmet and was fine. Which proves that helmets are useless.

I knew someone who drowned in a swimming pool. So anyone who doesn't wear a life jacket in the pool is a stupid idiot.

Once upon a time, "everyone knew" that the world was flat. So obviously it used to be, even though it isn't anymore.

Everyone should wear a helmet in the car, because if it saves even a single life, it's worth it.

All of which illustrates why the helmet debate is so pointless.