I have one, not nearly as horrid as all the rest.
My horse and I were at an event this year, our first one ever as a team, and I felt awesome. We had an amazing warm-up for our dressage, and we headed over to the dressage ring to ride our test. On the way over, Zip spooked at a baby stroller headed the other way. I recovered from that, no biggie, got him paying attention again, got back into my mindset. I hear the bell, enter at my trot, had a beautiful centerline, and was so focused on that perfect line I had just ridden... Zip kept that line right on over that tiny little white fence and up to the judge's booth.
I was disappointed, to say the least.