Do I wear a helmet? Ugh. I do when I am riding through a precarious part of town, meaning Midtown traffic. But when I'm riding on secure protected lanes or on the paths that run along the Hudson or through Central Park - no, I don't wear the dreaded helmet then.
The physical sensation of gliding with the wind in your face is exhilarating. That automatic activity of pedalling, when you have to be awake but not think too much, allows you to let subconscious thoughts bubble up, and things seem to just sort themselves out. And the adrenaline wakes you up if you weren't properly alert.