Oh how the neighbours laughed!
I recently fitted clipless to my road bike and have been on quite a few rides with no problems at all, plenty of traffic lights, give way junctions, not a problem! I always released one pedal to support myself when stopping but always had to look down when I was starting off again to locate the pedal which in inadvertently always seems to turn itself upside down.
So imagine my embarrassment to cruise up my drive way, with one pedal released and I decided to pedal a little further up the path, but the offending pedal hadn't turned and without looking my shoe engaged the pedal straightaway. A moment of sheer panic as the bike came to a stop and in slow motion, I lost any sense balance and over we went with the neighbour looking on, who was about to compliment me on my new bike!
There is something ironic about having a new road bike because the first thought I had was dont scratch it, its brand new! With this in mind I somehow managed to roll onto my back with the bike still attached to me. So I ended up having a conversation with my laughing neighbours lying flat on my back while still attached to bike still which was now directly above me.
So take heed, it does happen when your least likely to expect it!