What is it like to break bones and scrape skin off your knees and elbows? Let me just say that the he side of a truck is softer than the pavement. So when I saw this topic, I decided to write primarily because there are not a lot of people with my breadth of knowledge so perhaps something I write here will make sense to someone who reads it. I'm not going to quote statistics; I'll just sum them up by saying your chances of being killed on a motorcycle are far greater than any other mode of transportation. In fact, it is downright dreadful. I have learned a lot of things over time and I'll try to touch on a few that are the most dangerous and offer some real world tips. I'm not sure these are so much "unseen" dangers as "seen too late" dangers which are very real.
I am going to assume that you have been to the proper training courses, that you understand the basic physics of a motorcycle, and that you wear the proper attire, which means boots, gloves, eye wear and a helmet. Leather makes a great substitute for skin.
Walk around your bike and inspect it every time you ride. People can and do tamper with things, tires do deflate, and leaks and damage happen.
Avoid riding at night at all costs. Motorcycle headlight are poor in general. You will fail to see objects in the road, potholes, animals, gouges. Drunk people, the kind that don't see you, are more prominent at night. The dark is not your friend. Accidents at night are often bad or fatal. You should never drive at night but if you must, make it short and sweet. Don't ever drink and ride a motorcycle.
Motorcycles have about 6 square inches of rubber touching the pavement on each tire. Friction is what brings a bike to a stop. With 12 square inches of tire, stopping distances increase much more so than a car or light truck. Increase your following distances, 20 feet for every 10 MPH, to roughly double that of a car. Riding near the center of road will help you to avoid debris that slides off the crown and will also give yourself the widest field of vision when approaching blind intersections. Riding near the middle of the roadway gives you a little bit better reaction time should something like a dog come calling.
Don't ever assume anyone has seen you. Vehicles that turn left in front of you will be looking right at you. This situation is unavoidable but it happens.
Do not pass on highways that have driveways and several access roads intersecting them. People turning right sometimes only look left when entering the road.
If you make a sudden stop in traffic, immediately check your mirrors and make sure the closest vehicle or two is stopping in time. I ran a red light once because of this and saved myself from a rear end collision that would have sent me sprawling. Sometimes, you must choose the lesser of two evils.
Debris on the road such as blown out tires, animal carcasses and potholes can be navigated in a larger, four tire style vehicle., but not so readily on a bike.
If you are going to let the throttle out, find a safe and desolate place. Splitting lanes in heavy traffic on I-5 isn't one of them.
Motorcycles are gas efficient and they are the purest form of travel for many of us. Riding a motorcycle requires great vigilance and defensive driving all of the time. There are many unseen dangers for motorcyclists but that doesn't mean you can't reduce them or limit your risk. Respect your motorcycle, it will do the same for you.