I was once in a bad car accident - the car flipped over, we needed help getting out, etc. A man came over and help us get out of the car, then had another bystander make calls to family for us, and had another person call for an ambulance. He sat on the ground with me and made the driver of the other car (who caused the accident, but was for some reason enraged at us) stop screaming at us. He stayed with us until we were taken away in the ambulance. I have no idea who he was, but I've always been grateful for how he stepped in to help us the way he did.