I have been in a minor motorbike accident before resulting in some lacerations from scraping the asphalt and several fractures, nothing too serious.
First instinct was to get up and brush yourself off, looking at all the blood pouring out and not feel a thing and wondering what the hell just happened as your overdrived brain goes into a hyperactive state of activity and starts memorising and retaining the previous seconds of events in all its 1000 Frames Per Second (FPS) / High-Definition (HD) details and glory for permanent storage. The pain comes later when the epinephrine starts fading.
Some events can be so traumatic that excessive and prolonged amount of adrenal hormones actually destroy the neurons firing away in the brain thus resulting in memory loss etc. etc.
Sometimes you do not have control over the situation. You can be careful but the other party may not. With bicycle and motorcycle, your body protect the machine.
Motor fatal accidents are due to speed. My experience with motorcyclists is that they tends to wave in and out and wear dull clothing. Sometimes they appear suddenly beside you. For their own safety, they must follow the same traffic rules.