Remember kids... always wear a helmet. (The almighty bikeradar helmet thread)

I am sorry but common sense is a damn good starting point IF THERE IS NO EVIDENCE TO OVER-RULE COMMON SENSE. FFS is it really unreasonable of me to say that common sense says a bike helmet is better than a paper bag in a crash therefore I will choose the helmet until such time as the evidence tells me my common sense is wrong?

So your common sense tells you you should wear a helmet, my common sense say I shouldn't. Whose common sense is right and why?