Just the other night, I took an after work joy ride, twenty some odd miles, zipping along, dodging traffic, flying up and down hills and over bridges. I had this feeling come over me, like I was completely at one with my bike, the road, and the traffic, like I was doing a dance. Everything seemed natural, easy, instinctive, fluid, and free. I was pushing kinda hard for me. Eventually I pooped myself out, and the feeling passed, but there was an afterglow. I didn't occur to me at the time, but maybe it was endorphins.