It used to be cool to crap all over helmet laws, and it definitely feels cool to ride with the wind in your hair and nothing but the sun on your head. But ask anyone who has wrecked on their bike and they'll tell you- helmets are way cooler than death or brain damage.
Besides preventing a cracked skull a helmet also protects your head and face from a seriously painful case of road rash, which could leave you looking like Skeletor if you hit the street face first.
So strap that helmet on before you go riding so you can live to bike another day!