It's interesting to me how different countries approach helmets. In Germany some people wear them, but many don't. In the Netherlands wearing a helmet is practically unheard of.
I cycle in the UK, i wear a helmet because our cycling infra is not good, cyclists are not really protected by the police, and it's common to complain about cyclists. The attitude here is different. You're the enemy, a parasite, you're in the way of my car!