Originally Posted by RedRoan
But from this video I see horses pinning their ears, and kicking at his head
Just an amateur's thinking here, but... Horses rear when they are scared or angry. So, if you're not careful about how you teach them to rear on cue, scared/angry is what you get. Or, you teach them to rear by making
them scared or angry.
Also, random rearing does not = high school air.