I had two accidents that certainly made me think about it. Neither my fault but both had the potential of being fatal as they involved high speed moving large vehicles. Certainly they changed my attitude to riding and my riding overall. I never considered quitting but had I, I would have walked away without regret. Plenty of other activities to do in life besides motorcycling. Likely I would have bought a more expensive sportscar. Road riding today for me is admittedly less enjoyable. It is the main reason I trail ride and do track days. I still enjoy road riding but I keep seeing more and more reckless moves on the road. Rare is a day ride that I do not see something risky... certainly makes me think. But I also believe that when it is your time no matter what you are doing you will not avoid it.