and in response to the OP....
the blackness of the night and all its shades of purple, the orange light on the horizon, the lack of other traffic, the silence when you stop, the isolation, the riding in a bubble of light, the velvet darkness of the night sky, the "look at that moon", the "look at those stars", the "look out for that hole!", the damp patch on road surface you mistake for a pothole, the swooping owl you mistake for a bat, the bat you mistake for an owl, the deer crossing the road and not running away as you approach, the getting hopelessly lost and not caring, the satellites arcing across the sky, the meteors shooting earthwards, the way the hills are easier to climb when you can't see how steep or long they are, the waiting at a country crossroads for your mates to catch up with nothing but your own frosty breath for company, the unbeleiving drunks, the mystified drivers, the astounded shift workers, all of these and more, but most of all...
dawn over Seasalter, or over the Weald, or Romney Marsh, or the Downs above Chichester. I love night rides.