Wow, I hit the ground all the time on my little mare, I have the dusty britches award, but I'm older (and should be more afraid
) and I just don't have the balance I used to. And I don't get to ride a lot. But the only time she's scared me was when I tried to force her through the 'noodles' in the arena. I was basically just doing what I consider 'ground work' but on top of her. She went through on way fine (always do everything both ways, I have that pounding in my head from my BM) and when I turned her to go the other way she balked. I don't take balking well. So I urged her forward and she reared, and I fell off backward. I just had my bareback pad on her and she'd never done that before or since. I'll admit it scared me.
Once a friend of mine borrowed her to ride in the arena with her sister riding my friends horse. She told me later she got bucked off loping. I was stunned. (She used an English saddle) So I tacked up Sienna in said English saddle and fell off 8 times before I switched to her western saddle and made her lope. She has high withers and the saddle rubbed her, why more at a lope than a trot I don't know. Probably it didn't, more likely it's because a lope is just easier to buck at. She went fine with the western saddle but little things like that with equipment can cause a 1/2 way mannerly horse to get into habits that are very hard to break.