I think you need to be at least slightly more specific. Do you mean an accidental automobile collision? Or slipping on the stairs? Both? I’ve done both. Slipping and tripping has given me scars and body injuries and affected the way I relate to my physical body, danger, carefulness, running in socks, etc. Being in car accidents has also affected my thinking about danger driving and being a passenger in cars. I’m more aware of what can happen, and the potential for sudden great danger and consequences, which sometimes makes me a little nervous, at least in different circumstances and ways than before, but it also has me managing my driving differently, noticing more risks and taking fewer of them. The greatest effect that comes to mind was actually from very near accidents that I barely avoided (by some amazing driving). The biggest effect those had was to get me to notice that I had not been caring for my own safety much before that, which had me realize the extent of my depression and to change my life to correct the sources of the depression, because it was clear part of me that I’d been avoiding facing, was miserable. The biggest turning point for the better in my life.