I too wish I could put a horse into the ring again. Too old and way to fat now.
Wonderful horses to work with, ride and be around.
As for the moving fast, they are not running faster than human can run, but you are still moving at some speed, and they hit the ring at a trot, and they do work in the aisles at their home barns most of the time, so the horses are extremely used to horses dashing past them. Doesn't bother them a bit, and actually I've groomed some on string that would lean head sideways to watch one working too. Don't know if they had any training tips, but sure looked like they were studying them.
And the Roadster class! Go for the doctor and cover those drink cups!!!!
Best breed in the world to me...love them.
And as for what type of calm they can be?
I've brought horses on my string back to barn at Royal when the area was so crowded with people that I had to actually push people out of way, and the masses would close around the horse again, on all sides and never ever had one back an ear, or do anything but calmly walk through that crowd and never did a thing wrong.
Horses make me a better person.