Most of the falls I've had came from day dreaming while riding.
The front tire of a road bike (at least the narrow ones) are sensitive to being struck from the side. A lot of Houston streets have cracks and separations. While day dreaming, I've twice caught a tire in those spearations, or struck the side of the front tire on a big crack. The front wheel instantly pivots, and I do a face plant.
Riding a mountain bike on urban trails, I feel free to day dream, because the fat tires just roll over cracks, and holes and debris. But, one night I was riding a trail that crosses a four lane road. It was very dark, but I had ridden the trail many times I knew where the turns and twists where. As I got across the fourth lane, I rode into where I thought the curb cut to the trail was...I missed the curb cut and hit the curb at about a 45 degree angle...instant face plant.
The one crash that was not (all) my fault was caused by a car. On a very narrow street where most cars would drive about 25 mph, a car came up behind me and began honking for me to get out of his way. He could easily have moved to his left and gone around me, but he was insistant that I should get off the street.
So, I decided to ignore him. At that point, he moved up and tapped my rear tire with his front bumper. That sent me flying off the bike into the street. To my regret, by the time I got back on my bike, he had gone up the street, turned, and was out of sight. I was in a mood to put my New York u-lock to its second best use.
And, of course, within fifteen minutes of picking up a new bike with my first clipless pedals, I stopped at a stop sign and could not get unclipped. A slow sideways fall to the pavement. These days, I have BMX style pedals on all of my bikes...Houston has a stop sign or red light every hundred yards, so there is no reason to want to clip and unclip every thirty seconds.