A long time ago, on a galaxy far, far away .... Well, 1972 I think it was, I was riding my Suzuki T500 to work in Holborn, Central London. I was not concentrating as much as I should, and the sun was low behind me, so I missed the brake lights on the 6 volt Beetle in front of me.
That bike had Ferodo solo racing linings on the front brake - the OEM Suzuki ones were very prone to fade, but the Ferodo solo racing linings were prone to grab if not warm. I hit the brakes too hard and grab they did .
Next thing, I am lying on the ground with one leg under the bike, trapped. I was also in the outside lane. The commuters treated me as a chicane and drove round me. My mood was not improved by the smell of petrol and the sound of pinging of a hot two stroke engine cooling - but not nearly quickly enough for my liking. I was bruised but otherwise unhurt, but was becoming concerned about the hot engine/petrol interface.
Help came in the shape of Dave Potter, then the British 750 Champion, who was on his way to his work at Gus Kuhn's. He stopped his car and ran over to pull the bike off me, looked at my face when I removed my helmet, then laughed. I was a BMCRC Marshall at the time, and had picked him up off the ground a few weeks before. He commented that I was supposed to pick him up, not the other way round, and having made sure I was OK and the bike rideable, off he went, still amused.
Had he not stopped, I might have been there for a long time.