When I was about much younger (9-10 yrs old), I was always riding this pony named Justy. He was the sweetest thing! One day, I had him in the ring next to the mounting block so I could hop on. As I put my left foot into the stirrup, off he goes at a fast walk! I was literally hanging off the side of him with one foot in a stirrup, my hands and other leg grasping onto the saddle for dear life! Now I look back and think "Wow, he was only like 12 hands, why didn't I just make myself fall?"
I was actually taller than him at the top of his ear by probably a few inches! It was quite funny and needless to say ever since I have made sure the horse I am riding never moves away from the mounting block, while I am getting on!