I do not own a horse, but that doesn't mean crazy things do not happen.
Once, I was riding a stable horse named Cricket and was in for a normal ride. But, apparently Cricket had other ideas. First she shied over the bridge, then, at the "big open space," she galloped about 100 yards before she gave up. Then, a little while later, she saw a rabbit and loped 20 yards. By the time we got back to the stable, she was completely lathered in sweat.