experience
I don't need any more crash experience - I'll apply all my motorcycle exp and try to avoid any new. What I would share for others to keep in mind:
First rain in awhile - dirt and oils make road especially slick.
Other wet road concerns; painted lines, manhole covers, tracks, leaves etc. washed into road.
Insufficient light, more speed than sight. Potholes etc. are much worse when you don't see them. Obstacles you might roll over with anticipation take you down when you're not prepared. Oncoming car lights can limit visibility of dark objects at side of road - like a trash can or box put out for pickup.
Distraction - stop if you want to study a sight, riding requires full time attention. Quick peripheral glances at your own risk. Risk of distraction is directly proportional to speed, bigger, badder things happen faster.
Look past or between obstacles - we tend to go where we look. Also, looking over your shoulder alters your path, use mirrors and do the over shoulder only when your path is clear.
Euphoria - is great. Easily induced by riding bikes, mbs, motorcycles, horses, etc. But it can mess with your attention and self-preservation. Feel good, think safe.
Riding is not driving. It's an active, athletic endeavor even if you're cruising. There's a lot of sensory input that should stimulate your nervous system. This is more feel good and be more alive. Your reflexes and balance, muscle tone and awareness should be near peak when riding. This is what will keep you safe. Remember when you stop all this spools down, give it time to spool up again after a stop.
Ride more, have fun, be safe.
Thanks for this thread Mtn Man. I hope lots of people contribute and even more keep reading it. Practice awareness, the euphoria comes naturally.